Imide polymers

ABSTRACT

Glutarimide polymers having an acid and anhydride content lower than the acid and/or anhydride content normally present in the glutarimide polymers. Blends of the reduced acid and anhydride glutarimide polymers with thermoplastic materials are disclosed. A process for altering the properties of imide polymers by reducing or substantially removing acid and anhydride levels normally present in the imide polymer is also disclosed.

This is a divisional of application Ser. No. 452,991, filed Dec. 19,1989 now U.S. Pat. No. 4,954,574 which is a continuation of applicationSer. No. 108,383 filed 11/23/87,now abandoned, which is in turn adivisional of Ser. No. 770,034 filed 8/27/85, which issued as U.S. Pat.No. 4,727,117.

BACKGROUND OF THE INVENTION

This invention relates to imide polymers having acid and anhydridelevels less than are normally present in such polymers. This inventionalso relates to blends of the imide polymers, having lower than normalacid and anhydride levels, with other thermoplastic materials. Theinvention further contemplates a process for altering the properties ofimide polymers by reducing or substantially eliminating acid andanhydride functionality on the imide polymer.

U.S. Pat. No. 4,246,374 describes and claims polyglutarimide polymersand their preparation. The '374 patent teaches that the degree ofimidization of an acrylic polymer may vary from as low as 1% imidizationto about 100% imidization. The '374 patent teaches that imidization isaccomplished with anhydrous ammonia or an anhydrous primary amine.

U.S. Pat. No. 3,284,425 is directed to the preparation ofpolymethacrylimide products. The '425 patent discusses the possibilitythat acid or ester groups may become isolated between adjacent imiderings. The '425 patent also teaches the formation of polymethacrylimideproducts which ". . . are substantially free of carboxy or ester groups. . . in which the degree of imidization is at least about 95% . . . "Thus, the '425 reference, while recognizing the presence of acid groupsin the polyimides, teaches imidizing to at least about 95% imidizationin order to lower or remove the acid functionality of apolymethacrylimide.

Further, there is no recognition in the '425 patent concerning adverseeffects of the normal amount of acid and anhydride functionality on apolyimide polymer.

U.S. Pat. No. 4,518,717 describes a process for making imide polymers byreacting a monomeric dianhydride with a lactam or oxime to form abis-imide having an acid-group-carrying radical attached to the imidenitrogen. The bis-imide monomer is then esterified with a reactivesolvent that acts as an esterifying agent; methanol is typical. In theesterification process, the aromatic imide functionality is retained.The esterified bis-imide monomer is subsequently reacted with anaromatic diamine monomer in a polycondensation reaction, to form animide or amide-imide polymer.

European Patent Publication 007669, published Apr. 13, 1983, describesthe preparation of polyimides which are free from methyl substitution onthe nitrogen atom. The European publication teaches the preparation ofimide polymers free from methyl substitution on the nitrogen atomstarting from a non-crosslinked polymer which contains glutaricanhydride units. The polyglutaric anhydrides are reacted with ammonia toyield the desired polyimides free from methyl substitution on thenitrogen atom. As the degree of imidization exceeds 95% and approachescomplete imidization, the amount of residual acid and anhydride unitsremaining in the polymer chain becomes less significant, although thedegree of imidization, if above 95%, is a factor which limits theutility of the resultant polyimide. When the degree of imidization isless than 95%, then the residual acid and anhydride functionality on thepolymer chain results in less desirable properties than could beobtained when the acid and anhydride functionality is reduced oreliminated.

Makromol. Chem., 184, pages 1705-1726 (1983) discloses an analyticaltechnique for confirming the chemical structure of the reaction productsof polymethacrylic acid and formamide. The technique encompassestreating copolymers of methacrylic acid and methacrylimide withdiazomethane. There is no disclosure in the reference procedureconcerning the degree of imidization. Further, the imide groups arereacted along with the acid groups.

Japanese patent application 128,195, published Feb. 2, 1985, describes aprocess for preparing a polyglutarimide by condensing a polyamide or acopolymer of a methacrylamide with a methacrylate ester.

U.S. Pat. No. 4,458,046 discloses blends of vinyl chloride polymers andcopolymers of the styrene-maleimide type. The '046 patent teaches thatthe imide used be prepared from a dicarboxylic acid moiety and thatcomplete conversion of the dicarboxylic acid moiety to the desired imidebe obtained by using an excess of the stoichiometric amount of ammoniaor amine required for such conversion.

As a by-product of imidization of (meth)acrylic polymers by reactionwith ammonia or primary amines, anhydride and acid groups are formed onthe polymer chain. The acid and anhydride groups are intermediate in theformation of imide units. When the degree of imidization exceeds 95% andapproaches 100%, the amount of acid and anhydride units present on theresultant imide product decreases and poses less of a problem. However,when the degree of imidization exceeds 95%, particularly when anautoclave process is used, then a high degree of discoloration of theresultant polymer and degradation of the polymer itself is oftenobtained. The degradation of the polymer may also lead to alteration ofthe desirable properties of the resultant imide polymer.

When the degree of imidization of a polymer is 95% or less, then theamount of acid and anhydride functionality normally present on thepolymer chain as a natural incidence of the reaction involved becomesobjectionable in that the presence of acid and anhydride functionalitygenerally adversely affects the properties of the polyimide. Forexample, the presence of the normal amount of acid and anhydridefunctionality on an imide or polyglutarimide polymer will alter themiscibility of such polymer with other thermoplastic polymers.Additionally, acid and anhydride functionality affects theweatherability of a molded article prepared from such polymer in thatthe molded article will absorb more water as a result of the presence ofthe normal amount of acid and anhydride functionality. Further, highacid and anhydride functionality can result in higher melt viscositywhich would translate into the polymer being more difficult to processinto various molded articles.

It is an object of this invention therefore, to prepare a polyimidewherein the amount of acid and anhydride functionality is reduced fromthe amount normally present, or is substantially eliminated.

A further object of this invention is to prepare blends of polyimideswith other thermoplastic polymers wherein the acid and anhydridefunctionality of the polyimide in the blend has either been reduced fromthat which was originally present or has been substantially eliminated.

A still further object is to provide a process for reducing orsubstantially eliminating acid and anhydride functionality existing on apolyimide.

Other objects and advantages will become more apparent from thefollowing more complete description and claims.

DETAILED DESCRIPTION

Broadly, this invention contemplates a polymer containing glutarimideunits wherein the degree of imidization, by weight, on said polymer, andthe acid and anhydride functionality on said polymer, expressed inmilliequivalents per gram of imidizable components in said polymer, areas set forth below;

    ______________________________________                                        when the degree of imidizaton                                                                    the milliequivalents of acid                               on said polymer is and anhydride per gram are                                 ______________________________________                                        from about 1% to about 10%                                                                       0 to about 0.20                                            above about 10% to about 20%                                                                     0 to about 0.28                                            above about 20% to about 30%                                                                     0 to about 0.32                                            above about 30% to about 40%                                                                     0 to about 0.31                                            above about 40% to about 50%                                                                     0 to about 0.28                                            above about 50% to about 60%                                                                     0 to about 0.28                                            above about 60% to about 70%                                                                     0 to about 0.27                                            above about 70% to about 80%                                                                     0 to about 0.28                                            above about 80% to about 90%                                                                     0 to about 0.33                                            and above about 90% to about 95%                                                                  0 to about 0.40.                                          ______________________________________                                    

This invention also contemplates a blend of at least one thermoplasticpolymer and a second polymer, said second polymer being a polyimidepolymer as described in the immediately preceding paragraph.

This invention further contemplates a process for altering theproperties of a polymer containing imide units wherein the degree ofimidization is at least 1% and containing residual acidic or anhydridegroups comprising reacting said residual groups with an agent capable ofblocking the functionality of said groups.

It was surprising to find that when acid and anhydride functionality ofa polyimide was reduced or substantially eliminated, the resultantpolyimide then exhibited altered miscibility and compatibility withother thermoplastic polymers, better weatherability characteristics, anda lower melt viscosity thereby enhancing the processability of thepolyimide. The polyimide having reduced or substantially eliminated acidand anhydride functionality when compared to a polyimide which has theamount of acid and anhydride functionality normally present, is asuperior product.

The polyimides of the present invention also possess superior thermalstability. Preferred polyimides of this invention are those which have athermal stability indicated by a 1% weight loss, by thermogravimetricanalysis (TGA), at a temperature above 285° C. in air and above 300° C.in nitrogen.

As used in the specification and claims, the term "degree ofimidization" refers to the weight percentage of imide groups on apolymer in relation to the groups of the polymer capable of beingreacted to form imide groups. For example, one may have a copolymer ofstyrene and methacrylic acid. Because the styrene is not capable ofbeing imidized, the degree of imidization is based on the percentage ofimide groups which are subsequently formed from the methacrylic acidportion of the copolymer.

Any thermoplastic polyimide, containing acid and/or anhydride groups,may be used in practicing the process of this invention. For example,one may use the polyglutarimides disclosed in U.S. Pat. No. 4,246,374.The disclosure of U.S. Pat. No. 4,246,374 is incorporated herein byreference. Additionally, one may use a polymethacrylimide of the typeset forth in U.S. Pat. No. 3,284,425. The polyglutarimide product ofthis invention may be prepared from a polyimide such as those derivedfrom esters of acrylic or methacrylic acid wherein the ester moietycontains from about 1 to about 20 carbon atoms and which has beenreacted with ammonia or a primary amine wherein the hydrocarbon portionof the amine is hydrogen or a substituted or unsubstituted alkyl or arylgroup having up to about 20 carbon atoms, may also be used. Suchpolyimides are disclosed in U.S. Pat. No. 4,246,374. A preferredpolyimide is derived from methyl methacrylate.

The composition of the polyimide may be varied depending upon theproperties desired from the final product. A preferred polyimidecontains up to about 50%, and preferably from about 10% to about 50%, byweight, of acrylic or methacrylic ester units, preferably wherein theester moiety contains from 1 to about 20 carbon atoms. Another preferredpolyimide contains from about 50 to about 99%, by weight, of acrylic ormethacrylic ester units, with the preferred ester moiety as statedabove. Among the ester moieties, a more preferred one is methyl.

Among the polyimides which may be used to practice the process of thisinvention are the polyglutarimides described above and copolymersthereof with, for example, styrenic materials such as styrene, ringsubstituted styrenes, alpha-methyl styrene and the like, all optionallycontaining acrylonitrile, or methacrylonitrile and the like; polyimidescontaining succinimide functionality such as those prepared by thecopolymerization of an alkyl methacrylate with a maleimide orN-alkylmaleimides or N-arylmaleimide and the like; polyimides preparedby the copolymerization of alkyl methacrylates, maleimide and/or N-alkyland/or N-arylmaleimides, styrene and/or ring substituted styrenes oralpha-methylstyrene, all optionally containing acrylonitrile ormethacrylonitrile, and the like; copolymers of styrene, ring substitutedstyrenes, or alpha-methylstyrene with maleimide or N-alkylmaleimides, orN-arylmaleimides, and the like; copolymers of ethylene and propylenecontaining glutarimide functionality, and the like; graft polymers ofmethyl methacrylate or methacrylic acid onto polyethylene,polypropylene, or ethylenepropylene diene rubber, and the like;copolymers of maleic anhydride and olefins, followed by imidization, andgraft copolymers of maleic anhydride onto polyolefins followed byimidization, and the like; and copolymers of alkylmethacrylate, styrene,itaconimide, citraconimide, alpha-methylmaleimide or N-methylalpha-methylmaleimide, all optionally with acrylonitrile, and the like.Whichever polyimide is used to practice the process of this invention,such polyimide must have residual acid and/or anhydride groups.

Particularly preferred polyimides are those set forth in U.S. Pat. No.4,246,374 and, even more particularly preferred, are thepolyglutarimides prepared by the reaction of (1) poly(methylmethacrylate) with ammonia or methylamine and (2) a copolymer ofpoly(methyl methacrylate) and ethyl acrylate with ammonia or methylamineand (3) a copolymer of (methyl)styrene and methyl methacrylate withammonia or methylamine, because these polyimides are simple to prepareand easy to work with.

The polyimides may be prepared in any suitable manner and the inventionis not to be construed as being limited to the method of preparation ofthe polyimide. For example, one may prepare a polyimide by heating, withstirring, the selected polymer such as poly(methyl methacrylate), in anautoclave, in the presence of a primary amine, such as butylamine ormethylamine. Other suitable amines include aniline and cyclohexylamine;ammonia is also suitable for preparing the polyimide. The reaction maybe conducted in the presence of water and at an elevated pressure suchas between about 8 and about 85 atmospheres. The temperature which maybe used may vary from about 180° C. to about 350° C., with theunderstanding that the pressure used will vary with the temperatureused.

One may also prepare a polyimide as described in U.S. Pat. No. 4,246,374wherein an extruder is used in the preparation. Generally, when using anextruder, the polymer, such as poly(methacrylic acid) may becontinuously fed to an extruder and ammonia or a primary amine, such asmethylamine, may be introduced continuously through an injection port.Unwanted by-products and excess ammonia or primary amine are removed byprogressively reducing the pressure at downstream extruder vents. Thetemperature in the extruder may be varied and such variation will bedependent on the nature of the starting materials, pressure being used,residence time, melt viscosity of the polymer being extruded, etc.Generally, a temperature of from about 200° C. to about 450° C. may beused in preparing the polyimide and a pressure may be used which is fromabout atmospheric to about 1000 atmospheres, although pressures of lessthan 500 atmospheres are generally suitable. The reaction time of theacrylic polymer in the reaction zone of the extruder will generally varyfrom about 0.1 to about 1000 seconds and preferably from about 30 toabout 300 seconds. The desired degree of imidization is obtained bysuitable adjustment of various reaction parameters such as residencetime. The extruder is generally equipped with a screw which advances thematerials present through the extruder. In a particularly preferredembodiment, the extruder may be equipped with at least one pair ofscrews. The number of pairs of screws which is present in the extruderis dictated solely by economic and practical process conditions. In oneembodiment, each screw member of each pair of screws which is present inthe extruder may rotate in a direction counter to the rotationaldirection of the other screw member of the pair. In this manner mixingmay be enhanced, as may removal of undesired materials.

The polyimide may also be prepared in a tubular reaction vessel such asa baffled in-line mixer, wherein the baffles provide the necessarymixing. The baffled in-line mixer may also be equipped with variousports for the introduction of necessary reactants or materials.

It is preferred that an extruder be used and that the extruder which isused for preparing the polyimide, be equipped with at least one pair ofscrews wherein each member of the pair rotates in a direction counter tothe rotational direction of the other screw member of the pair.

Because the preparation of the polyimide may involve amide and/or acidintermediates which may give rise to imides or anhydrides, if anextruder apparatus is not used to prepare the polyimide, the finalproduct may contain imide, amide, acid, anhydride and ester moieties.The preference for the reaction to take place in the extruder is for thereason that the proper use of the extruder tends to cause allsignificant amide groups to further react to imide although some acidand anhydride groups are still present. Thus, polyimides prepared usingan extruder are usually substantially free of amide functionality andcontain less acid and anhydride functionality than polyimides preparedusing other processes.

The invention is not to be construed as limited to any particular methodfor preparing polyimides.

Regardless of which apparatus or method is used for preparing thepolyimides, the degree of imidization should be controlled so that thefinal product has from about 10% to no more than about a 95% degree ofimidization. It is preferred however that the degree of imidization ofthe polyimide be from about 25% to about 95%, more preferred that thedegree of imidization be from about 40% to about 88%, and still morepreferred that the degree of imidization be from about 50% to about 85%.

In a preferred embodiment of the present invention, the acid andanhydride functionality of polyimide having up to about 88% degree ofimidization is reduced to about 0.25 or fewer milliequivalents per gramof imidizable polymer component, and in a more preferred embodiment theacid and anhydride functionality of a polyimide having up to about 85%degree of imidization is reduced to about 0.25 or fewer milliequivalentsper gram of imidizable polymer component.

If the degree of imidization exceeds 95%, then, although the acid andanhydride level of such a polyimide may be low, such polyimides maysuffer from a high degree of discoloration, a partially degradedpolymer, and undesirable alteration of the properties of the polyimide.

Although the final polyimide product of this invention has no more thanabout a 95% degree of imidization, the process of this invention may beused to remove acid and anhydride functionality from a polyimidecontaining such functionality wherein the degree of imidization of suchpolyimide exceeds 95% and is less than 100%.

The agent which is used to remove or reduce the acid and anhydridefunctionality may be any agent which is capable of reacting with theacid and anhydride groups and incapable of reacting with the imidefunctionality and which will not adversely affect the properties of thepolyimide, either during the time the reaction with the acid andanhydride functionality is being conducted or in the final polymer.

The term acid and anhydride functionality, as used in the specificationand claims, means any carboxylic acid, carboxylic acid salt, and/oranhydride group present on the polyimide.

Among the types of agents which may be used to partially or completelyremove acid and anhydride groups which are present on the polyimide arealkylating agents such as orthoesters, ketals, carbonates, sulfoxidesand the like. Other agents, including esterification agents, may also beused such as siloxanes, silyl ethers, silylenol ethers, trialkylphosphates, trialkyl phosphites, dialkyl sulfates, alkylalkylsulfonates, alkyl arylsulfonates, dialkyl carbonates, diarylcarbonates, aryl isocyanates, carbodiimides, trialkylsilyl halides, enolesters, alcohols, alkyl esters, alkyl isocyanates, quaternary ammoniumsalts, ureas, guanidines, and the like.

Among the specific agents which may be used to remove acid and anhydridefunctionality are dimethyl carbonate, 2,2-dimethoxypropane, dimethylsulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethylorthoformate, diphenyl carbonate, dimethyl sulfate, methyltoluenesulfonate, methyl trifluoromethylsulfonate, methyl acetate,methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate,dimethyl carbodiimide, dimethyl t-butylsilyl chloride, isopropenylacetate, dimethyl urea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-n-butoxysilane, dimethyl(trimethylsilyl)phosphite, trimethyl phosphite, trimethyl phosphate, tricresylphosphate, and the like.

The amount of agent used to remove acid and anhydride functionality willvary depending upon the amount of acid and anhydride present. This maybe readily determined by the titration method described hereafter. Theamount of agent used will generally be at least the stoichiometricamount of agent needed to remove the acid and anhydride functionality ifit is desired to remove substantially all acid and anhydridefunctionality. Generally, when removing all acid and anhydridefunctionality from the polyimide, it is desirable to use from about a10% to about a 50% excess above stoichiometry of the agent.

When it is desired to remove only a portion of the acid and anhydridefunctionality, then it is preferred to use less than a stoichiometricamount of agent to avoid removing more acid and anhydride functionalitythan is desired.

In some instances, the agent used may react with water which isassociated with the polyimide. In such instances, procedures may be usedto assure that the desired amount of agent is present to react with theacid and anhydride groups present on the polyimide. One procedure is todry the polyimide, for example, under vacuum at a temperature of fromabout 100° C. to about 135° C. for about 8 to about 20 hours. A secondprocedure is to use an excess, above the amount of agent required, sothat the excess amount of agent will react with the water present andthe desired amount of agent will react with the acid and anhydridegroups present on the polymide.

The reaction wherein the acid and anhydride functionality is removed orreduced may be conducted in a single or multi-screw extruder, in anautoclave, in a continuously recirculated pipe reactor, in a baffledin-line mixer which may be used in series with an extruder, in awipingfilm evaporator, a falling film reactor or evaporator, in a discextruder or reactor, or other melt-mixing device or the like.

If the reaction is conducted using an extruder, then it may be conductedas a continuous process wherein a polyimide is prepared in an extruderand is then passed, in the extruder, into a zone wherein the agent isintroduced and the polyimide is contacted with the agent for a period oftime of from about 15 seconds to about 20 minutes at a temperature offrom about 150° C. to about 400° C. and at a pressure of from aboutatmospheric to about 15000 kiloPascals (2200 psi), in the absence of anysolvent and/or catalyst.

Alternatively, a polyimide, which has been previously prepared, may beintroduced into an extruder at an elevated temperature so as to form amolten mass, and may then be contacted with the agent at the aforesaidtemperature and pressure.

If the reaction of the agent and the acid and anhydride groups is to beconducted in an autoclave, then the reaction may take place, with orwithout a solvent for the polyimide, in the autoclave for a period oftime of from about 10 minutes to about 8 hours at temperatures of fromabout 100° C. to about 180° C. and in an unpressurized vessel or apressurized vessel at pressures to about 1000 atmospheres. In someinstances, the agent, if a liquid, may also act as the solvent for thepolyimide. In other instances a separate solvent may be used.

The solvent used may vary widely depending on the nature of thepolyimide solute to be reacted. Generally, the solvent should be atleast somewhat polar in nature and should be non-reactive with the agentto be used. If the agent is not to also act as the solvent for thepolyimide then the solvent should also be non-reactive with thepolyimide.

Among the solvents which may be used are diglyme, triglyme, sulfolane,tetrahydrofuran, tetrahydropyran and the like.

Yet another method for conducting the reaction of the polyimide with theagent is to melt the polyimide in the autoclave and to conduct thereaction between the acid and anhydride groups of the polyimide and theagent in a molten state without the addition of any solvent.

Still another method is to prepare the polyimide in a reaction vessel,such as an autoclave, and, as the very last step in the preparation, toadd a suitable agent for the removal of the acid and anhydride groups.

If one is to conduct a continuous reaction to prepare a polyimide andremove or reduce acid and anhydride functionality, whether in anextruder, autoclave or other reaction vessel, then the amount of acidand anhydride groups present on the polyimide may be determined by firstconducting the imidization reaction under the conditions to be used inthe extruder, autoclave or other reaction vessel and measuring theamount of acid and anhydride groups present on the resultant polyimide.In this manner, one may predetermine the amount of agent to be added, ifa continuous process is to be utilized, to remove the desired amount ofacid and anhydride groups. In some cases by-products or unreactedmaterials from the imidization reaction may enhance or impede thesubsequent reaction of the polyimide with the agent.

If desired, the reaction of the agent with the polyimide may beconducted in the presence of a catalyst. The catalyst preferablycatalyzes the reaction of the agent with the polyimide, but does notcatalyze degradation of the polyimide nor cause other undesirablereactions. Among the catalysts which may be used are base catalysts suchas trimethylamine, triethylamine, benzyldimethylamine,tetramethylammonium hydroxide and the like. One may also use acidcatalysts or Lewis acid catalysts such as p-toluenesulfonic acid,tetrabutyl titanate, manganese tetracetate and the like.

Optionally, the polyimide may be the final stage in a multistage polymerand the reaction is conducted with the entire multistage polymer.Further, the polyimide may be one of the elements of a block or graftcopolymer, and the reaction is conducted in the presence of the entireblock or graft copolymer.

In another embodiment, the polyimide may be in the core of a multistagepolymer or in the second or other intermidiate stage of a multistagepolymer and the acid and anhydride functionality may be removed asaforesaid. The amount of acid and anhydride functionality on any of thepolyimides of the stages of the multi-stage polymer may be adjusted tothat which is desired.

The polyimides of this invention may be blended with one or more otherthermoplastic polymers and may even be blended with another polyimidewhich may or may not have had its acid and anhydride level reduced orsubstantially eliminated. The polyimide according to this invention maybe blended, as a multi-stage polymer, wherein at least one of the stagesis a polyimide according to this invention, with another thermoplasticpolymer.

Generally, when blending polyimides prepared according to thisinvention, with other thermoplastic polymers, the amount of polyimidepresent may vary widely from about 1% to about 99%, by weight of theentire composition.

The advantage of blending a polyimide of this invention with at leastone other thermoplastic polymer is that the resultant blends generallyexhibit a better combination of properties which may include better meltviscosity, greater compatibility and/or miscibility, greaterweatherability, greater impact resistance, better ductility, and bettersolvent resistance than the combination of properties of blends ofpolyimides which have not undergone diminution or substantial removal ofacid and anhydride functionality.

The polyimides of this invention, particularly the polyglutarimides, maybe blended with other thermoplastic polymers (as used herein "-"indicates blended polymers, "/" copolymers, and "//"" graft or blockpolymers) such as butadiene/styrene/(meth)acrylic,styrene/(meth)acrylic, and (meth)acrylic multistage polymers;butadiene/styrene rubbers, ethylene/propylene/diene rubbers, polyamides,polyamide-multistage polymer blends, ethylene/vinyl acetate,styrene/acrylonitrile, styrene/acrylonitrilemultistage polymer blends,styrene/acrylonitrile-ethylene/propylene/diene rubber blends,alpha-methylstyrene/acrylonitrile,alpha-methylstyrene/styrene/acrylonitrile, alpha-methylstyrene/methylmethacrylate/ethyl acrylate, butadiene//acrylonitrile/styrene,polycarbonate, polycarbonate-multistage polymer blends, polybutyleneterephthalate, polybutylene terepthalate-polycarbonate blends,polybutylene terephthalate-multistage polymer blends, polybutyleneterephthalate/polytetrahydrofuran, polyvinyl chloride, polyvinylchloride-multistage polymer blends, polyvinyl chloride-(meth)acrylateblends, chlorinated polyvinyl chloride,acrylonitrile/(meth)acrylatemultistage polymer blends,acrylonitrile/(meth)acrylate/styrene, epichlorohydrin/bisphenol-A,polyethylene terephthalate or other polyalkylene terephthalate,polyethylene terephthalate-glycol modified, polyethyleneterephthalate-polycarbonate blends, polycaprolactone, polyarylate,copolyester of bisphenol-A with isophthalic and/or terephthalic acids,poly(meth)acrylates, polyacetal, polystyrene, high-impact polystyrene,styrene/maleic anhydride, styrene/maleimide, polyolefins, polyvinylidenefluoride, polyvinylidene fluoride-multistage polymer blends,cellulosics, polyethylene oxide, polyamideimide, polyetherester,polyetheresteramide and polyetheramide. Blends having modifiedperformance characteristics can be prepared from any other polymersystems with polyimides. These include polyphenylene sulfide,polyphenylene oxide, polysulfone, polyphenylene oxidestyrene blends,polyphenylene oxide-high impact polystyrene blends, polyvinylidenechloride, polyvinylidene chloride/(meth)acrylonitrile, polyvinylidenechloride/(meth)acrylate, polyvinyl alcohol, polyvinyl acetate,polyetheretherketone, polyetherimide, thermoplastic polyimides, andother polymer types. Random or block copolymers which combine thedifferent functionalities can also be used, and ternary or higher blendscan be made from combinations of any of these polymer types with theimide polymers.

The imide polymers and blends with other polymer systems can be furthermodified by the incorporation of glass or other fibers, or particulatefillers or reinforcing agents such as talc or other minerals, glassspheres, or metallic particles. In general, the imide polymers exhibitgood adhesion to glass and other inorganic fillers. Further modificationof properties of the polyimides and blends can be obtained byincorporating additives such as flame retardants, blowing agents,antioxidants, thermal stabilizers, pigments, flatting agents,lubricants, antistatic agents, conductive materials, toners or UVstabilizers.

In the Examples which follow, certain tests are conducted. These testsare as follows:

The Vicat is determined by ASTM Test Method 1525-65T using 40 milpenetration and heating rate B.

The total acid and anhydride functionality was determined by titratingsolutions of the polymers in either 1:1 methylene dichloride-methanol or3.75:1 dimethyl sulfoxide-water. A 0.3-g sample of the polymer isdissolved in 75 ml of methylene dichloride-methanol. A measured volumeof 0.1N sodium hydroxide solution, containing more than enough base toneutralize the acid and anhydride in the sample, is added to the polymersolution, and the excess base is titrated with 0.1N hydrochloric acid.The total acid and anhydride functionality is the difference, inmilliequivalents, between the added base and the acid solution used toreach neutrality, corrected by subtracting the acid titration value of asolvent blank (the blank is usually less than 5% of the total acid andanhydride functionality). If dimethylsulfoxide is used, the polymer isdissolved in 75 ml of dimethylsulfoxide, and 20 ml of water is added tothe solution, which is then titrated as above. In the samples below, theend point of the titration was detected either colorimetrically orpotentiometrically, and in some instances other solvents were used toprepare the polymer solution for titration.

The total acid and anhydride functionality of a copolymer or blendcontaining polymer components that are imidizable is calculated asmilliequivalents per gram of the imidizable polymer components.

Molecular weight is determined by gel permeation chromatography using acommercial Waters instrument and a tetrahydrofuran solvent, and is aweight average molecular weight.

Dynamic thermogravimetric analysis (TGA), as used herein, is a standardtest conducted using a programmed temperature-increase rate of 20° C.per minute and an atmosphere of either air or nitrogen, as indicated.Results given herein for TGA were either obtained using, or areconsistent with those obtained using, a duPont thermogravimetricanalyzer in combination with a differential thermal analyzer; specificoperating instructions for the TGA instrument and for this particulartest are described in E. I. duPont de Nemours, Inc. Instrument ProductsDivision Preliminary Product Bulletin 950-1(A-36177).

Although compatibility and/or miscibility of blended polymers is notnecessary to the compositions of the present invention, compatibilityand/or miscibility of such blends may be enhanced by reduction of theacid and anhydride functionality. Measurements of glass transitiontemperature (T_(g)) and visual examination of polymer samples, asdescribed below, help to quantify observations of such compatibilityand/or miscibility enhancement.

The glass transition temperature (Tg) of polymer and blend samples isdetermined by differential scanning calorimetry (DSC), using aPerkin-Elmer Model DSC-2 calorimeter. The sample is heated in a nitrogenatmosphere at 20° C. per minute, and the reference material in thecalorimeter is 60-80 mg aluminum. The Tg value is taken from the DSCchart as the temperature at the midpoint of the transition. All blendsamples, prior to the DSC run, are preheated for one minute at atemperature 20° C. higher than the higher Tg value for either componentin the blend, and then cooled to a temperature below the lower Tg valueof either component.

The DSC values for Tg are usually sufficient to indicate whether a blendis miscible. However, if the Tg values of the two components aresimilar, or if one of the components undergoes a phase change (e.g.melting or recrystallization) near the Tg of the other component, theDSC result may not be adequate to detect whether the sample is miscible.In such a case other techniques for detecting miscibility may be used.For examples, domains indicating incompatibility in blend samples may bedetected by transmission electron microscopy (TEM), and the sensitivityof this technique may, under some conditions, be enhanced, as bystaining one of the phases. An example of this is staining phasescontaining carbon-carbon unsaturation using osmium tetroxide.

Compatibility or miscibility of polymer blends is determined by anexamination of the blend of the polyimide with a specified polymer aftermastication of the blend in a Brabender mixing device at a temperatureof from 193° to 246° C. for ten minutes in an air atmosphere. Samples ofthe resulting blend are removed from the melt, formed into small,flattened "buttons" and examined visually for clarity. With some blends,the refractive indices of the two polymers are similar at roomtemperature, and incompatibility is difficult to detect by visualexamination of the button sample. In such a case the button is observedat several different temperatures; the refractive indices of twoimmiscible components will change at different rates if one component isheated above its glass transition temperature.

In the examples which follow, the percent nitrogen of the polyimidesused is set forth. The degree of imidization, by weight, may becalculated from the percent nitrogen given: divide the percent ofnitrogen actually present in the polyimide by the theoretical amount ofnitrogen at 100% imidization and multiply by 100.

In order to more fully illustrate the nature of this invention and themanner of practicing the same, the following examples are presented.

EXAMPLES 1 THROUGH 10

A polyglutarimide having N-methylimide groups, prepared in accordancewith the procedure disclosed in U.S. Pat. No. 4,246,374, is used. Theimide was prepared from a feedstock of poly(methyl methacrylate) havinga weight average molecular weight of 200,000.

The extruder used is a 2.0 cm-diameter (0.8 inch) Welding Engineersnon-intermeshing twin screw extruder. The extruder has one section aboutsix diameters long, for introducing and plasticating the polyglutarimidefollowed by a closed barrel section about 6 diameters long for pumpingand pressure generation, followed by the reaction zone. This zone, about31.5 diameters long, comprises a ported barrel section for introducingblocking agents, closed barrel sections, and a venting section forremoving volatile products. Another vented section, operated atsubstantially atmospheric pressure, follows the reaction zone, forremoving additional volatiles.

The extruder is purged with the polyglutarimide, to remove contaminants.The polyglutarimide is then added to the plastication zone of theextruder at a rate of 60 grams per minute. At this time the barreltemperature in the reaction zone is about 300° C., and the blockingagent pressure is about 3500 kiloPascals (500 psig). The polymer residesin the extruder for an average of about 120 seconds.

The polyglutarimide used has a nitrogen content of 7.13 weight percent,as determined by micro Kjeldahl analysis, and a Vicat of 170° C.

The initial, total acid and anhydride of the polyglutarimide used is0.585±0.020 milliequivalents per gram of imidizable component in thepolymer.

In ten separate experiments, the polyglutarimide described above wasprocessed in the extruder. For eight of the runs, trimethyl orthoformatewas used for removing anhydride and acid functionality from thepolyglutarimide. The extruder screw speed was, for all examples, 400rpm. The trimethylorthoformate (TMOF) was pumped through a port into theinlet section of the extruder where it reacted with the polyglutarimideat a temperature of from 200° C. to 350° C. and a pressure of 3450±70kiloPascals (500±10 psig).

In Table I, the letter "d" means that, prior to introduction in theextruder, the polyglutarimide is dried, under vacuum, at a temperatureof 135° C. for eight to twelve hours. The letter "u" means that thepolyglutarimide is not dried prior to introduction into the extruder. InExamples 3 and 4, no excess TMOF is added to the extruder. Table I setsforth the results obtained.

                                      TABLE I                                     __________________________________________________________________________                Ratio (equivs./    Acid & Anhy-                                        Agent feed                                                                           equivs.) of                                                                           Extruder                                                                            Vicat of                                                                           dride Content                                  Example                                                                            rate (grams/                                                                         Agent to Acid                                                                         Reac. Zone                                                                          final pro-                                                                         of Final Prod-                                 No.  minute)                                                                              and Anhydride                                                                         Temp. °C.                                                                    ducts °C.                                                                   duct (meq./g.)                                 __________________________________________________________________________     1 d+                                                                              none   0.00    313   170  0.585                                           2 u+                                                                              none   0.00    304   170  0.569                                          3 d  1.9    0.52    298   165  0.264                                          4 u  1.9    0.52    290   170  0.545                                          5 d  4.4    1.17    291   160  0.032                                          6 u  4.8    1.30    298   160  0.300                                          7 d  8.2    2.21    286   160  0.033                                          8 u  7.8    2.08    292   160  0.032                                          9 d  10.7   2.86    297   160  0.065                                          10 u 10.9   2.92    299   161  0.031                                          __________________________________________________________________________     +Comparative                                                             

Example 4 illustrates that when the polyglutarimide is not dried priorto reaction with the agent, there is an effect on the amount of agentavailable to react with acid and anhydride groups. In Example 5 (dried),a slight excess of agent, over the stoichiometric amount required, isused. The slight excess in Example 6 (undried), which is substantiallythe same as Example 5, results in a higher acid and anhydride contentbecause of the reaction of water with the agent used, whereas in Example5, the reaction is substantially quantitative. Example 8 (undried)illustrates that the effect of the reaction of water and TMOF can beovercome by using a sufficient excess of TMOF over the stoichiometricamount required.

EXAMPLES 11 THROUGH 14

The procedure of Examples 1-10 was repeated except that the agent usedwas triethyl orthoformate (TEOF), to convert the acid and anhydridefunctionality to an ethyl ester; all polyimides used were undried; thepolyimide feed rate was 3 grams/minute; the TEOF feed rate is set forthin Table II; the screw speed of the extruder was 250 rpm; thetemperature in the zone for reacting TEOF with the acid and anhydridegroups was 302° C. The percent nitrogen in each of the polyimides of theexamples was 7.13 wt. %. The initial acid and anhydride level ofpolyimide used was 0.585±0.020 milliequivalents per gram (meq./g)determined as in Examples 1-10. The results are set forth in Table II.The pressure in the reaction zone was 2900 kiloPascals (420 psig) forExample 12; 2345 kiloPascals (340 p sig) for Example 13, and 2070kiloPascals (300 psig) for Example 14.

                  TABLE II                                                        ______________________________________                                              Agent    Ratio (equivs./                                                                           Vicat                                              Ex-   Feed rate                                                                              equivs.) of of fin-                                                                              Acid & Anhydride                            ample (grams/  agent to acid                                                                             al prod-                                                                             Content of Final                            No.   minute)  and anhydride                                                                             uct (°C.)                                                                     Product (meq./g.)                           ______________________________________                                         11+  none     0.00        170    0.585                                       12     6.3     2.11        157    0.066                                       13    13.8     4.62        158    0.081                                       14    22.4     7.50        158    0.093                                       ______________________________________                                         +Comparative                                                             

Examples 13 and 14 show that the removal of acid and anhydride groups issubstantially complete in Example 12 and that the additional agent usedin Examples 13 and 14 has little benefit over the amount of agent usedin Example 12. The amount of acid and anhydride remaining in Examples12, 13 and 14 are substantially the same and are within the experimentalerror of the titration method used, which is the same as is used inExamples 1-10.

EXAMPLES 15 THROUGH 20

The procedure of Examples 11 though 14 were repeated except that theagent used was trimethyl orthoformate (TMOF) and the polyimide used is a201° C.-Vicat ammonia polyimide which has a nitrogen content of 7.72weight %. The polyimide used had an acid and anhydride content of 0.610milliequivalents per gram of polyimide, as determined by titrating it ina 3.75/1.0 dimethylsulfoxide/water solution. The polyimide samples usedwere not dried. The polyimide feed rate was 30 grams per minute. Thepressure in the reaction zone was 2205 kiloPascals (320 psig) forExample 16; 3585 kiloPascals (520 psig) for Example 17; 3655 kiloPascals(530 psig) for Example 18; 3205 kiloPascals (465 psig) for Example 19;and 3035 kiloPascals (440 l psig) for Example 20.

The results are set forth in Table III.

                  TABLE III                                                       ______________________________________                                              Agent    Ratio (equivs./                                                                           Vicat                                              Ex-   Feed rate                                                                              equivs.) of of fin-                                                                              Acid & Anhydride                            ample (grams/  agent to acid                                                                             al prod-                                                                             Content of Final                            No.   minute)  and anhydride                                                                             uct (°C.)                                                                     Product (meq./g.)                           ______________________________________                                         15+  none     0.0         201    0.610                                       16    1.0      0.48        198    0.432                                       17    1.9      0.97        198    0.311                                       18    2.9      1.45        192    0.000                                       19    3.9      1.93        190    0.000                                       20    7.7      3.81        192    0.000                                       ______________________________________                                         +Comparative                                                             

EXAMPLES 21 THROUGH 27

The purpose of these examples is to illustrate a continuous process formaking polyimides and reducing or substantially eliminating acid andanhydride functionality. In this continuous process, the amount of acidand anhydride of the polyimide prior to treatment with an agent may bedetermined by removing a sample of polyimide prior to reaction with theagent for reducing acid and anhydride functionality and titrating theamount of acid and anhydride present. A calculated amount of the agent,based on the desired acid and anhydride level, may then be added.Alternatively, prior to running the continuous process, one maydetermine the amount of agent to add by preparing the polyimide underthe same conditions to be used in the continuous process, and thenmeasuring the acid and anhydride level. As long as the feed stock isconverted to the same polyimide and treated with the agent under thesame conditions, the resultant final product should be substantially thesame in both cases.

The apparatus of examples 1-10 is used in examples 21 through 27 exceptthat an imidization zone measuring 2.0 cm by 61 cm (0.8 inch by 24inches) is added to the apparatus as the first zone. The imidizationzone also contains a double screw. The feed which is added to theimidization zone is poly(methyl methacrylate) (PMMA) having a weightaverage molecular weight of 148,000. The PMMA feed rate is 45 grams perminute. To the PMMA in the imidization zone is added methylamine. Thebarrel temperature of the imidization zone was 302° C.±5° C. The gaugepressure in the imidization zone for Example 21 was 6137 kiloPascals(890 psig); for Example 22 was 6205 kiloPascals (900 psig); for Example23 was 6275 kiloPascals (910 psig); for Example 24 was 6275 kiloPascals(910 psig); for Example 25 was 6171 kiloPascals (895 psig); and forExample 26 was 7240 kiloPascals (1050 psig). In Example 21 and 26 thepolyimides were not treated with any agent after preparation. Theprocedure of Examples 1-10 for removing acid and anhydride was thenrepeated. The agent used was trimethyl orthoformate (TMOF). Thetemperature of the TMOF/polyimide reaction zone was 304° C.±5° C. Thepressure in the TMOF/polyimide reaction zone for Example 22 was 2413kiloPascals (350 psig); for Example 23 was 3172 kiloPascals (460 psig);for Example 24 was 3103 kiloPascals (450 psig); for Example 25 was 3068kiloPascals (445 psig); for Example 26 was atmospheric pressure (0.00psig); and for Example 27 was 3103 kiloPascals (450 psig).

Table IV sets forth the results obtained.

                                      TABLE IV                                    __________________________________________________________________________         Rate of for-                                                                        Methyl-                                                                              Agent  Ratio (equivs./                                                                       Poly-           Acid & Anhydride                  mation of                                                                           amine  feed   equivs.) of                                                                           imide                                                                             % Nitro-                                                                            Polyimide                                                                           Content of final             Example                                                                            polyimide                                                                           feed rate                                                                            rate   agent to acid                                                                         Vicat                                                                             gen of                                                                              wt. av,                                                                             product                      No.  (gram/min)                                                                          (grams/min)                                                                          (grams/min)                                                                          and anhydride                                                                         (°C.)                                                                      Polyimide                                                                           -- M × 10.sup.-3                                                              (meq./g.)                    __________________________________________________________________________     21+ 38.8  14.6   0.00   0.00    168 6.80  131   0.575                        22   38.8  14.6   1.46   0.61    164 6.63  130   0.251                        23   38.8  14.6   3.10   1.31    157 6.83  127   0.000                        24   38.8  14.6   4.85   2.05    158 6.79  131   0.000                        25   38.8  14.6   8.73   3.69    157 6.77  138   0.000                         26+ 38.4  19.9   0.00   0.00    184 7.34  119   0.678                        27   38.4  17.9   8.73   3.16    168 7.33  128   0.000                        __________________________________________________________________________     +Comparative                                                             

EXAMPLES 28 to 34

The procedure of Examples 11 through 14 was repeated with the followingchanges. In Examples 28, 31, 33 and 37 the imides were not treated withan agent to substantially remove or reduce acid and anhydridefunctionality. The agent used in Examples 29, 30 and 32 was dimethylcarbonate (DMC). Examples 30 and 32 also utilized triethylamine (TEA) asa catalyst for the reaction between the agent and the acid and anhydridegroups. The TEA was added at a feed rate of 0.09 gram per minute inExample 20, and 0.11 gram per minute in Example 32. The agent used forExamples 34-36 was 2,2-dimethoxypropane (DMP). The polyimide used inExamples 28 through 30 was polymethylimide having a Vicat of 172° C. anda nitrogen content of 7.04 weight percent. The polyimide used inExamples 31 and 32 was a polymethylimide having a Vicat of 150° C. and anitrogen content of 4.90 weight percent. The polyimide used in Examples33-36 was a polymethylimide having a Vicat of 170° C. and a nitrogencontent of 7.24 weight percent. The polymide used in Examples 37 and 38was a polymethylimide having a Vicat of 162° C. and a nitrogen contentof 3.08 weight percent. The pressure in the agent reaction zone was 2900kiloPascals (420 psig) for Example 29; 2793 kiloPascals (405 psig) forExample 30; 2137 kiloPascals (310 psig) for Example 32; 2124 kiloPascals(308 psig) for Example 34; 2827 kiloPascals (410 psig) for Examples 35and 36; and 2137 kiloPascals (310 psig) for Examples 38.

Examples 28-30 used polyimide dried in the manner of Examples 1-10.Examples 31-38 used an undried polyimide. The initial acid and anhydridelevel of the polyimide of Examples 28-30 was 0.618 milliequivalents pergram (meq/g) of polyimide. The polyimide of Examples 33-36 had aninitial acid and anhydride level of 0.570 meq/g. The polyimide ofExamples 31 and 32 was prepared from a 90/10 methyl methacrylate/styrenefeedstock and contained 4.90 weight percent nitrogen and an initial acidand anhydride level of 0.689 meq/g of imidizable polymer component. Thepolyimide of Examples 37 and 38 was prepared from a 73.5/24.5/2.0 methylmethacrylate/alpha-methylstyrene/ethyl acrylate feedstock, and had anitrogen content of 3.08 weight percent and an initial acid andanhydride level of 0.975 meq/g of imidizable polymer component. Theresults are set forth in Table V.

                                      TABLE V                                     __________________________________________________________________________         Agent                                                                              Ratio (equivs./                                                                            Vicat                                                       Feed rate                                                                          equivs.) of  of fin-                                                                            Acid & Anhydride                                  Example                                                                            (grams/                                                                            agent to acid                                                                              al prod-                                                                           Content of Final                                  No.  minute)                                                                            and anhydride                                                                         Agent.sup.1                                                                        uct (°C.)                                                                   Product (meq./g.)                                 __________________________________________________________________________     28+ none 0.00         172  0.618                                             29   4.3  2.56    DMC  163  0.087                                             30   4.2  2.51    DMC  162  0.005                                                       0.05    TEA                                                          31+ none 0.00         150  0.689                                             32   5.2  3.15    DMC  144  0.020                                                       0.06    TEA                                                          33+ none 0.00         170  0.570                                             34   2.1  1.19    DMP  169  0.478                                             35   4.4  2.48    DMP  166  0.376                                             36   8.6  4.86    DMP  166  0.345                                              37+ none 0.00    none 162  0.975                                             38   9.0  3.15    TMOF 150  0.040                                             __________________________________________________________________________     .sup.1 DMC = dimethyl carbonate                                               TEA = triethylamine                                                           DMP = 2,2dimethoxypropane                                                     TMOF = trimethyl orthoformate                                                 +Comparative                                                             

EXAMPLES 35 THROUGH 44

These examples illustrate the removal of acid and anhydridefunctionality from polyimides using a solution reaction. The polyimideused for Examples 35 through 44 was the polyimide of Examples 1-10. Theprocedure for Examples 35-44 is as follows.

To a 3-neck, 500 ml round-bottom flask equipped with a magnetic stirrerand reflux condenser is added 250 ml. of a solvent. A 12.5-g polyimidesample is dissolved in the solvent and the agent is then added to thesolution. The resulting solution is then heated to a temperature of from160° C. to 175° C., under nitrogen, for varying periods of time. Thesolution is then cooled to room temperature and the final product isprecipitated by adding it to methanol; it is then filtered and dried.The acid and anhydride level of the final product is determined as inExamples 1-10. The results are given in Table VI.

                                      TABLE VI                                    __________________________________________________________________________                                    Acid & Anhy-                                            Agent.sup.1                                                                         Reac-                                                                             Reac-                                                                             Ratio (equivs./                                                                       dride content                                           and grams                                                                           tion                                                                              tion                                                                              equivs.) of                                                                           Content of                                    Example   of    Temp.                                                                             Time                                                                              agent to acid                                                                         Product                                       No.  Solvent                                                                            Agent (°C.)                                                                      (hrs.)                                                                            and anhydride                                                                         (meq./g.)                                     __________________________________________________________________________     35+ diglyme                                                                            none/0.0                                                                            160 8.0 0.0     0.508                                         36   diglyme                                                                            TMOF/7.6                                                                            160 4.0 9.8     0.170                                         37   diglyme                                                                            TMOF/7.6                                                                            160 8.0 9.8     0.061                                         38   triglyme                                                                           TEOF/10.6                                                                           175 2.0 9.8     0.385                                         39   triglyme                                                                           TEOF/10.6                                                                           175 3.5 9.8     0.227                                         40   triglyme                                                                           TEOF/10.6                                                                           175 5.0 9.8     0.128                                         41   triglyme                                                                           TEOF/10.6                                                                           175 7.0 9.8     0.063                                         42   triglyme                                                                           TEOF/10.6                                                                           175 8.2 9.8     0.065                                         43   dimethyl-                                                                          DMSO/275                                                                            170 3.0 482     0.263                                              sulfoxide                                                                44   dimethyl-                                                                          DMSO/275                                                                            170 7.0 482     0.217                                              sulfoxide                                                                __________________________________________________________________________     .sup.1 TMOF = trimethl orthoformate                                           TEOF = triethylorthoformate                                                   DMSO = dimethylsulfoxide                                                      diglyme = diethyleneglycol dimethyl ether                                     triglyme = triethyleneglycol dimethyl ether                                   +Comparative                                                             

EXAMPLES 45 THROUGH 49

The purpose of these Examples is to demonstrate the change in chemicalresistance for the various polyimides which have been prepared. Thefollowing Examples utilize the imides prepared in earlier Examples.

Examples 45 utilizes the polyimide prepared in Example 1

Example 46 utilizes the polyimide prepared in Example 12.

Example 47 utilizes the polyimide prepared in Example 5.

Example 48 utilizes the polyimide prepared in Example 26.

Example 49 utilizes the polyimide prepared in Example 27.

The imides used in Examples 45 and 48 were not treated to remove acidand anhydride groups. The polyimides used in Examples 48 and 49 wereprepared using a continuous process for the preparation of the polyimideand removal of acid and anhydride groups.

The polyimides used in these Examples were injection molded to form5.1×1.3×0.32-cm (2×0.5×0.125-inch) bars. The weights of the molded barswere determined and each bar was immersed in a different solvent, whichwas kept at a temperature of 23° C., for seven days. The bars were thenremoved from the solvent and the percent weight gain or weight loss wasthen measured by reweighing the bars. For determining water absorption,a 0.25-mm-thick film of imide was prepared by compression moldingpredried imide pellets. The film was dried, weighed, immersed in waterfor fourteen days at a temperature of 50° C., and reweighed.

The results are set forth in Table VII.

                                      TABLE VII                                   __________________________________________________________________________    Water Absorp-                                                                 tion         Percent Wt. Change-Immersion at 23° C. for 7 days              (% Weight                                                                             Ammonium        1,1,1-tri-                                       Example                                                                            Loss or Hydroxide       chloro-                                          No.  Gain)   (10% aq.)                                                                           Methanol                                                                           Ethanol                                                                            ethane                                                                             Toluene                                     __________________________________________________________________________     45+ 4.9     12.3  14.9 1.7  0.37 0.18                                        46   3.3     0.98  No Data                                                    47   3.8     0.83   7.1 0.64 -13  -35                                          48+ 6.0     16.5  19.3 2.52 0.23 0.28                                        49   3.9     0.85   8.3 0.82 -11  -33                                         __________________________________________________________________________     +Comparative                                                             

As can be seen from Table VII, those polyimides which have had acid andanhydride levels reduced or substantially eliminated absorb less waterthan polyimides having untreated acid and anhydride levels. Thisindicates that weatherability would be better for those polyimideshaving reduced acid and anhydride levels.

Table VII also demonstrates that resistance to ammonium hydroxide,methanol and ethanol is better for those polyimides which have beentreated to substantially remove or reduce acid and anhydride levels whencompared to untreated polyimides.

Table VII also demonstrates that the treated polyimides are somewhatsoluble in 1,1,1-trichloroethylene and toluene whereas the untreatedpolyimides are not soluble. This indicates that the treated polyimidesmay be dissolved, to some extent, in some solvents and may therefore beused as coating compositions whereas the untreated polyimides are notsoluble in those solvents.

EXAMPLES 50 THROUGH 57

These examples demonstrate the effect of weathering on various polymideswhich have been treated with an agent to remove acid and anhydridegroups. The polyglutarimides used in Examples 54 through 57 correspondto the polyglutarimides used in Examples 50 through 53 except that theprocedure of Examples 1 through 10 is used to treat thepolyglutarimides. The agent used in treating the polyglutarimides is, ineach case, trimethyl orthoformate. Example 54 is the treated counterpartof Example 50; Example 55 is the treated counterpart of Example 51;Example 56 is the treated counterpart of Example 52; and Examples 57 isthe treated counterpart of Example 53. The milliequivalents of acid andanhydride per gram of imidizable group are set forth in Table VIII. Theweight percent nitrogen for each of the polyglutarimides used is alsoset forth in Table VIII.

The weathering tests employed a Xenon Arc Weather-o-meter in themodified (extreme) test mode, according to ASTM method G26-83. Testsamples were molded into 5.1×7.6 ×0.32-cm (2×3×0.12-inch) plaques. Thetest conditions include a 2-hour cycle: 80 minutes dry (76.7° C. blackbody temperature, 50% relative humidity) and 40 minutes wet (sprayeddistilled water). The light level was 6500 watts throughout. Table VIIIsets forth the results obtained.

                                      TABLE VIII                                  __________________________________________________________________________               Milliequiva-                                                                         Total Hrs. Of Exposure in                                              lents of Acid                                                                        Weather-o-meter vs Degree of                                Example                                                                            %     & Anhydride                                                                          Surface Crazing.sup.1                                       No.  Nitrogen                                                                            Per Gram                                                                             500                                                                              1000                                                                             1500                                                                              2000                                                                             2500                                                                             3000                                        __________________________________________________________________________    50+  5.28  0.349  N  N  N   VL VL MH                                          51+  6.27  0.460  N  N  N   VL VL H                                           52+  6.87  0.624  N  N  VL  L  H  VH                                          53+  7.59  0.798  N  VL LM  MH VH VH                                          54   5.66  0.033  N  N  N   N  N  N                                           55   6.39  0.035  N  N  N   N  N  N                                           56   7.06  0.002  N  N  N   N  N  N                                           57   7.04  0.002  N  N  N   N  N  MH                                          __________________________________________________________________________     .sup.1 N = none                                                               VL = very light                                                               L = light                                                                     LM = light to medium                                                          M = medium                                                                    MH = medium to heavy                                                          H = heavy                                                                     VH = very heavy                                                               +Comparative                                                             

As can be seen from Table VIII, when a polyglutarimide is treated tosubstantially remove or reduce the acid and anhydride levels, theweatherability of the resultant treated polyglutarimide is much superiorto that of the untreated polyglutarimides.

EXAMPLES 58 THROUGH 72

A number of N-methyl polyglutarimides were prepared in accordance withthe teachings of U.S. Pat. No. 4,246,374. Some of the polyglutarimideswere then treated with an agent in the manner of Examples 1 through 10.The polyglutarimides prepared in Examples 58 through 72 were thenevaluated for miscibility and compatibility with other polymers. Aletter designation is assigned to each example and that letterdesignation is utilized in later examples in which miscibility andcompatibility properties are given. Table IX sets forth thepolyglutarimide and its properties. The T_(g) was determined bydifferential scanning calorimetery.

                                      TABLE IX                                    __________________________________________________________________________                        Degree              No. Av.                                                                             Milliequivalents                                % Nit-                                                                            Imidi-                                                                             Treated (T)                                                                          Wt. Av. Mole-                                                                         Molecular                                                                           of Acid & Anhydride             Example                                                                            Letter                                                                            Vicat  rogen                                                                             zation by                                                                          or Untreated                                                                         cular Wt.                                                                             Weight                                                                              per gram of Imidi-              No.  ID  °C.                                                                        T.sub.g                                                                          by Wt.                                                                            Weight                                                                             (UT)   × 10.sup.-3                                                                     × 10.sup.-3                                                                   zable Component                 __________________________________________________________________________    58   A   150 147                                                                              5.6 67   .sup.  160     68.0  0.504                           59   B   146 143                                                                              5.6 67   T      157     66.5  0.101                           60   C   165 162                                                                              6.5 78   .sup.  124     49.6  0.452                           61   D   157 155                                                                              6.4 76   T      120     49.0  0.094                           62   E   167 164                                                                              6.8 81   .sup.  131     54.5  0.513                           63   F   157 158                                                                              7.1 84   T      124     53.7  0.011                           64   G   170 168                                                                              6.9 82   .sup.  145     62.4  0.624                           65   H   160 158                                                                              7.1 84   T      129     56.4  0.002                           66   I   170 168                                                                              7.1 84   .sup.  116T    51.5  0.585                           67   J   169 165                                                                              7.0 83   T      110     42.8  0.512                           68   K   162 162                                                                              7.0 83   T      110     45.7  0.354                           69   L   161 158                                                                              7.0 83   T      107     44.5  0.191                           70   M   156 155                                                                              6.9 82   T      107     44.5  0.045                           71   N   179 175                                                                              7.6 91   .sup.  135     59.9  0.798                           72   O   165 163                                                                              7.5 90   T      115     47.2  0.002                           __________________________________________________________________________     Molecular Weights are determined by gel permeation chromatography in          tetrahydrofuran. Milliequivalents of acid and anhydride per gram of           imidizable group is determined by titration using methylene                   dichloride/methanol as set forth in other examples.                      

EXAMPLES 73 THROUGH 81

A number of 50/50 weight/weight blends were prepared with thepolyglutarimides of Examples 58 through 72. The polymer blended with thevarious polyglutarimides was a styrene-acrylonitrile copolymer composedof 75% by weight styrene and 25% by weight acrylonitrile. The T_(g) forthe polyglutarimide, the blend of polyglutarimide and polymer, and thepolymer with which the polyglutarimide was blended, was determined. Thepresence of a single T_(g) for the blend indicates completecompatibility.

The blends were prepared by melt mixing the polyglutarimide and thestyrene-acrylonitrile copolymer in a Brabender melt mixer at atemperature of 232° C. Small (0.9×0.15-cm) buttons were formed from themelt.

Table X sets forth the results obtained.

                  TABLE X                                                         ______________________________________                                                 Polyglutar-                                                                             Observed T.sub.g                                           Example  imide Used                                                                              Values       Appearance of                                 No.      (Table IX)                                                                              °C.   Blend                                         ______________________________________                                         73+     I         165/113      Opaque                                        74       J         165/113      Opaque                                        75       K         161/114      Translucent                                   76       L         154/119      Almost Clear                                  77       M         128          Clear                                          78+     E         178/113      Opaque                                        79       0         131          Clear                                          80+     E         164/112      Translucent                                   81       F         130          Clear                                          82+     C         157/113      Translucent                                   83       D         125          Clear                                          84+     A         125          Clear                                         85       B         124          Clear                                         ______________________________________                                         +Comparative                                                             

In Examples 73 through 77, the following should be noted. Theglutarimide of Example 73 has not been treated with any agent to removeacid and anhydride functionality. The polyglutarimides of Examples 74through 77 have been treated to remove acid and anhydride functionalitybut the amount of acid and anhydride remaining varies so that, as oneproceeds from Example 74 through Example 77, the milliequivalents ofacid and anhydride in each of these examples changes. Example 73 has0.585 milliequivalents of acid per gram of imidizable group; Example 74has 0.512 milliequivalents of acid; Examples 75 has 0.354milliequivalents of acid; Example 76 has 0.191 milliequivalents of acid;and Examples 77 has 0.045 milliequivalents of acid. As the amount ofacid and anhydride in the polyglutarimide decreases, the compatibilityof the polyglutarimide with the styrene-acrylonitrile copolymerincreases as is seen by the appearance or by the single T_(g) of theblend. In Examples 78 through 85, all of the even-number examples are ofpolyglutarimides which have not been treated to remove acid andanhydride functionality. The immediate following, odd-numbered exampleis of the same polyglutarimide treated to remove acid and anhydridefunctionality. It is therefore clear that compatibility of the treatedpolyglutarimides with styrene-acrylonitrile copolymer is enhanced.Attention is invited to Example 84, wherein the polyglutarimide is nottreated and the blend is clear and shows a single T_(g) for the blend.It is known from U.S. Pat. No. 4,436,871 that certain polyglutarimidesare compatible with styrene-acrylonitrile copolymers even though nosteps have been taken to remove acid and anhydride functionality.

EXAMPLES 86 THROUGH 89

The procedure of Examples 73 through 85 was repeated except that thepolymer with which the polyglutarimide was blended is changed. Thepolymer used in Examples 86 through 89 was Abson® 89140 which is an ABS(acrylonitrile/butadiene/styrene terpolymer supplied by Mobay ChemicalCompany.) All polymer blends were opaque to translucent rather thanclear, due to the fact that the initial index of refraction between therubber and hard phases does not match. However, appearance of a singleT_(g) for the blend indicates compatibility of the polyglutarimide withthe ABS polymer (T_(g) values for the rubber phase are not shown). Theresults are set forth in Table XI.

                  TABLE XI                                                        ______________________________________                                                 Polyglu-  Observed T.sub.g                                           Example  tarimide  Values       Appearance of                                 No.      Used      °C.   Blend                                         ______________________________________                                         86+     N         168/108      Opaque                                        87       O         129          SemiOpaque                                     88+     E         155/108      Translucent                                   89       F         128          Hazy clear                                    ______________________________________                                         +Comparative                                                             

As is seen from Table XI, Examples 86 and 88 utilize polyglutarimideswherein no steps have been taken to remove acid and anhydridefunctionality from the polyglutarimide. The results of Examples 87 and89 show a single T_(g) for the blend thus demonstrating compatibility ofthe treated polyglutarimide with the polymer. The material in Example 87is the material from Example 86, but treated. Similarly, the material inExample 89 is the material from Example 88, but treated.

EXAMPLES 90 THROUGH 97

The procedure of Examples 73 through 85 was repeated except that thepolymer used was Blendex® 586, obtained from Borg-Warner Company. It isbelieved that Blendex 586 is a teropolymer of alphamethylstyrene/styrene/acrylonitrile. The results are expressed in TableXII.

                  TABLE XII                                                       ______________________________________                                        Example   Polyglutar-                                                                             Observed T.sub.g                                          No.       imide Used                                                                              Values °C.                                                                         Appearance                                    ______________________________________                                         90+      N         171/129     Opaque                                        91        O         142         Clear                                          92+      G         161/128     Opaque                                        93        H         138         Clear                                          94+      C         140         Clear                                         95        D         137         Clear                                          96+      A         136         Clear                                         97        B         134         Clear                                         ______________________________________                                         +Comparative                                                             

Attention is invited to the fact that in Examples 90 and 92, thepolyglutarimide is not treated to remove acid and anhydridefunctionality and the blends are opaque. In Examples 94 and 96, thepolyglutarimides are also not treated to remove acid and anhydridefunctionality and the blends are clear and exhibit only a single T_(g)for the blend. The difference resides in the fact that the degree ofimidization for Examples 96 and 94 are 67% and 78%, respectively, andthe acid and anhydride levels for Example 96 is 0.504 milliequivalentsand for Example 94 is 0.452 milliequivalents. When Examples 96 and 94are compared with Examples 90 and 92, it is seen that Examples 90 and 92have a higher degree of imidization and a higher acid and anhydridecontent. The degree of imidization for Example 90 is 91% and the amountof acid and anhydride is 0.798 milliequivalents and the degree ofimidization for Example 92 is 82% and the acid and anhydride content is0.624 milliequivalents. Although the blends for certain non-treatedpolyglutarimides are clear and exhibit only a single T_(g), otherproperties are altered, such as weatherability.

EXAMPLES 98 TO 119

Examples 98 to 119 show that polycarbonate of two different molecularweights and Phenoxy® resin (a condensation polymer of epichlorohydrinand bisphenol-A) all show partial to almost complete miscibility withvarious imides upon melt blending. The alkylated imides uniformly showhigher miscibility with these polycarbonate polymers. The similarity ofimide and polycarbonate T_(g) 's makes the DSC data in some of the belowcases a less reliable indication of miscibility. In these cases thephysical appearance is a more important gauge of miscibility. Theresults of these examples are shown in Table XIII.

                                      TABLE XIII                                  __________________________________________________________________________         Imide                                                                             Imide                                                                              Imide            Observed                                       Exam-                                                                              Source                                                                            Vicat                                                                              T.sub.g (°C.)                                                              Imide                                                                             meq/g                                                                             Imide/                                                                             T.sub.g (°C.)                           ple  (Exam-                                                                            (°C.)/                                                                      by  % by                                                                              total                                                                             Polymer                                                                            by   Appear-                                   No.  ple)                                                                              Type.sup.1                                                                         DSC.sup.2                                                                         wt..sup.3                                                                         acid.sup.4                                                                        Ratio                                                                              DCS.sup.5                                                                          ance.sup.6                                __________________________________________________________________________     98+ 71  179UC                                                                              175 91  0.798                                                                             50/50                                                                              178/150                                                                            OP                                        99   72  165/C                                                                              163 90  0.002                                                                             50/50                                                                              165/152                                                                            OP/TL                                      100+                                                                              62  167/UC                                                                             164 81  0.513                                                                             50/50                                                                              166/152                                                                            OP                                        101  63  157/C                                                                              158 84  0.011                                                                             50/50                                                                              155 (Bd.sup.7)                                                                     OP/TL                                      102+                                                                              60  165/UC                                                                             162 78  0.452                                                                             50/50                                                                              149 (Bd.sup.7)                                                                     OP                                        103  61  157/C                                                                              155 76  0.094                                                                             50/50                                                                              146 (Bd.sup.7)                                                                     OP/TL                                      104+                                                                              58  150/UC                                                                             147 67  0.504                                                                             50/50                                                                              143 (Bd.sup.7)                                                                     OP                                        105  59  146/C                                                                              143 67  0.101                                                                             50/50                                                                              142 (Bd.sup.7)                                                                     OP/TL                                      106+                                                                              62  167/UC                                                                             164 81  0.513                                                                             80/20                                                                              159  TL                                        107  63  157/C                                                                              158 84  0.111                                                                             80/20                                                                              159  TL/TP                                      108+                                                                              62  167/UC                                                                             164 81  0.513                                                                             20/80                                                                              150  TL                                        109  63  157/C                                                                              158 84  0.011                                                                             20/80                                                                              152  TL/TP                                      110+                                                                              71  179UC                                                                              175 91  0.798                                                                             50/50                                                                              175/147                                                                            OP                                        111  72  165/C                                                                              163 90  0.002                                                                             50/50                                                                              164/148                                                                            OP/TL                                      112+                                                                              62  167/UC                                                                             164 81  0.513                                                                             50/50                                                                              167/159                                                                            OP                                        113  63  157/C                                                                              158 84  0.011                                                                             50/50                                                                              152  OP/TL                                      114+                                                                              60  165/UC                                                                             162 78  0.452                                                                             50/50                                                                              149 (Bd.sup.7)                                                                     OP                                        115  61  157/C                                                                              155 76  0.094                                                                             50/50                                                                              149 (Bd.sup.7)                                                                     OP/TL                                      116+                                                                              58  150/UC                                                                             147 67  0.504                                                                             50/50                                                                              149 (Bd.sup.7)                                                                     OP                                        117  59  146/C                                                                              143 67  0.101                                                                             50/50                                                                              140 (Bd.sup.7)                                                                     OP/TL                                      118+                                                                              64  170/UC                                                                             168 82  0.624                                                                             50/50                                                                              162/104                                                                            OP/TL                                     119  65  160/C                                                                              158 84  0.002                                                                             50/50                                                                              118  Clear                                     __________________________________________________________________________     .sup.1 Imides are all undried methyl imides; UC = unalkylated, C =            alkylated.                                                                    .sup.2 Undried imides.                                                        .sup.3 Imide weight % imidization level calculated for methyl imides form     100 (% N/8.377% = I.                                                          .sup.4 Titrable acid in the imide per gram of sample (0.020 meq/g,            titrated in MDC/MeOH  1/1                                                     .sup.5 Since the PC and imide T.sub.g 's are similar, appearance is a         better test of miscibility in this case.                                      .sup.6 OP = Opaque; TL = translucent; TP = transparent; CL = clear.           .sup.7 Bd = Broad                                                             +Comparative                                                                  Note: The blended polymer for Examples 98-109 is Polycarbonate M50, for       Examples 110-117 is Polycarbonate M39, and for Examples 118 and 119 is        Phenoxy resin.                                                           

EXAMPLES 120 to 125

Examples 120 and 121 show that Dylark® 332 (approximately86/14-styrene/maleic anhydride, by our analysis) is miscible with a 67%imidized alkylated methyl imide (imide from Example 59), but not withthe corresponding unalkylated imide (imide from Example 58).

An ammonia imide was prepared by treating Dylark 332 at 49 g/m and 260°C. in an extruder with 3.9 g/m anhydrous ammonia at 2826 kPa or 410psig. according to the Kopchik process (U.S. Pat. No. 4,246,374). Theresulting imide contained from 0.000 to 0.070 meq/g of acidicfunctionality and had a nitrogen level of 1.88 weight percent (for 14.1%maleimide, % N theoretical=2.01%), indicating about 94 weight %imidization. The Vicat for Dylark 332 was 136° C., (T_(g) =130° C.) andfor the ammonia imide was 151° C. (T_(g) =145° C.).

When the same unalkylated and alkylated methyl imides used in Examples120 and 121 were melt blended with this Dylark-based ammonia imide, bothblends were observed to be largely to completely miscible, indicating aninherently greater interaction between the acrylic imides and themaleimides versus the maleic anhydride polymer. When the Dylark 332ammonia derivative was melt blended with a more highly imidized,unalkylated (Example 124) and alkylated (Example 125) acrylic imide,miscibility differences could again be observed between the alkylatedand unalkylated blends. Following the previous pattern, the alkylatedimide (imide F, Example 125) was completely miscible, while theunalkylated imide (imide E, Example 124) was only partially miscible.

                                      TABLE XIV                                   __________________________________________________________________________         Imide                                                                             Imide                      Observed                                  Exam-                                                                              Source                                                                            Vicat                                                                              Imide                                                                             Imide                                                                             meq/g                                                                             Polymer/                                                                            Poly-                                                                             T.sub.g (°C.)                      ple  (Exam-                                                                            (°C.)/                                                                      T.sub.g                                                                           % by                                                                              total                                                                             Polymer                                                                             mer by   Appear-                              No.  ple)                                                                              Type.sup.1                                                                         (°C.)                                                                      wt..sup.3                                                                         acid.sup.4                                                                        T.sub.g                                                                             Ratio                                                                             DCS  ance.sup.5                           __________________________________________________________________________     120+                                                                              58  150/UC                                                                             147 67  0.504                                                                             Dylark-                                                                             50/50                                                                             143/130                                                                            OP                                                             332/130                                             121  59  146/C                                                                              143 67  0.101                                                                             Dylark-                                                                             50/50                                                                             134  TL                                                             332/130                                              122+                                                                              58  150/UC                                                                             147 67  0.504                                                                             Imide A.sup.6 /                                                                     50/50                                                                             147  TL/CL.sup.7                                                    145                                                 123  59  146/C                                                                              143 67  0.101                                                                             Imide A.sup.6 /                                                                     50/50                                                                             146  CL                                                             145                                                  124+                                                                              62  167/UC                                                                             164 81  0.513                                                                             Imide A.sup.6 /                                                                     50/50                                                                             150 Bd.sup.8                                                                       OP                                                             145                                                 125  63  157/C                                                                              158 84  0.011                                                                             Imide A.sup.6 /                                                                     50/50                                                                             153  CL                                                             145                                                 __________________________________________________________________________      .sup.1 Imides are all undried methyl imides; UC = unalkylated, C =           alkylated.                                                                    .sup.2 For undried imides.                                                    .sup.3 Imide weight % imidization level calaculated for methyl imides fro     100 (% N/8.377%) = % I.                                                       .sup.4 Milliequivalents of titratable acid in the imide per gram of sampl     (± ca. 0.020 meq/g, titrated in MDC/MeOH  1/1).                            .sup.5 OP = opaque; TL = translucent; TP = transparent; CL = clear.           .sup.6 Imide A is the ammonia imide prepared from Dylark 332, as describe     in the text.                                                                  .sup.7 Clear with a trace of turbidity.                                       .sup.8 Bd = Broad                                                             +Comparative                                                             

EXAMPLES 126 to 134

Examples 126 to 134 show that polyvinylidene fluoride (Kynar® 720) ismiscible with alkylated methyl imide but not unalkylated methyl imide(at this imidization level), thus following the same pattern as seenpreviously. The blends in examples 128 and 129 were prepared on aBrabender melt-mixing device, while examples 130 to 134 were extrusionblended on a 1" Killion extruder. Kynar polyvinylidene fluoride (PVDF)is a crystalline polymer which shows a large crystallization endotherm(CE) by DSC analysis, which obscures any nearby amorphous T_(g) inpolyvinylidene fluoride and any nearby T_(g) in the blended imidepolymer (Example 128). Since it is crystalline, it is also translucentto opaque. The miscibility of polyvinylidene fluoride and the imide fromExample 65 (Example 129) supresses crystallization, giving an amorphouspolymer blend with a single T_(g). The levels of clarity and T_(g) 's ofthe blends indicate that while either miscibility or mixing was notcomplete in all samples, the level of miscibility was quite high. Thetensile properties of the imide/Kynar blends also indicate that aslittle as 5% Kynar polymer gives a ductile material as measured bytensile elongation. The percent elongation to break for Examples 126 and130-134 are: 5% for Example 126, (no yield), 11% for Example 134,(greater than 6% elongation indicates yielding), 67% for Example 133,72% for Example 132, 83% for Example 131, and 101% for Example 130. Thatimides may be used to provide an amorphous polyvinylidene fluoride isalso clear from these results.

                                      TABLE XV                                    __________________________________________________________________________         Imide                                                                             Imide                                                                              Imide       Blended                                                                             Imide/                                                                            Observed                                  Exam-                                                                              Source                                                                            Vicat                                                                              T.sub.g (°C.)                                                              Imide                                                                             meq/g                                                                             Polymer/                                                                            Poly-                                                                             T.sub.g (°C.)                      ple  (Exam-                                                                            (°C.)/                                                                      by  % by                                                                              total                                                                             Polymer                                                                             mer by   Appear-                              No.  ple)                                                                              Type.sup.1                                                                         DSC.sup.2                                                                         wt..sup.3                                                                         acid.sup.4                                                                        T.sub.g                                                                             Ratio                                                                             DCS.sup.5                                                                          ance.sup.8                           __________________________________________________________________________     126+                                                                              64  170/UC                                                                             168 82  0.624                                                                             --    100/0                                                                             168  CL                                    127+    --   --  --  --  Kynar 0/100                                                                             CE.sup.5                                                                           OP/TL.sup.6                                                    720/CE.sup.5                                         128+                                                                              64  170/UC                                                                             168 82  0.624                                                                             Kynar 50/50                                                                             CE.sup.5                                                                           OP/TL.sup.6                                                    720/CE.sup.5                                        129  65  160/C                                                                              158 84  0.002                                                                             Kynar 50/50                                                                             78.sup.5                                                                           CL                                                             720/CE.sup.5                                        130  65  160/C                                                                              158 84  0.002                                                                             Kynar 75/25                                                                             126  TL                                                             720/CE.sup.5                                        131  65  160/C                                                                              158 84  0.002                                                                             Kynar 80/20                                                                             130  TL                                                             720/CE.sup.5                                        132  65  160/C                                                                              158 84  0.002                                                                             Kynar 85/15                                                                             138  T/CL.sup.7                                                     720/CE.sup.5                                        133  65  160/C                                                                              158 84  0.002                                                                             Kynar 90/10                                                                             145  CL/TL.sup.7                                                    720/CE.sup.5                                        134  65  160/C                                                                              158 84  0.002                                                                             Kynar 95/5                                                                              152  CL                                                             720/CE.sup.5                                        __________________________________________________________________________     .sup.1 Imides are all undried methyl imides; UC = unalkylated, C =            alkylated.                                                                    .sup.2 For undried imide.                                                     .sup.3 Imide weight % imidization level calculated for methyl imides from     100 (% N/8.377%) + % I.                                                       .sup.4 Milliequivalents of titratable acid in the imide per gram of sampl     (± ca. 0.020 meq/g, titrated in MDC/MeOH  1/1).                            .sup.5 CE indicates crystallization endotherm which obscures any amorphou     T.sub.g in polyvinylidene fluoride and any nearby T.sub.g in the blended      imide polymer.                                                                .sup.6 Polyvinylidene fluoride is translucent to opaque due to                crystallinity.                                                                .sup.7 Appearance T/CL was translucentto-clear (clear with a trace of         turbidity), while CL/T was completely clear.                                  .sup.8 OP = Opaque; TL = Translucent; TP = Transparent; CL = Clear            +Comparative.                                                            

EXAMPLES 135 TO 143

The miscibility of Kynar 720 polyvinylidene fluoride (PVDF) may beexploited to provide enhanced impact resistance in imide blendscontaining grafted rubber impact modifiers. Example 135 shows typicalimpact, tensile, and heat-distortion temperature data for animpact-modified blend of unalkylated, 170° C. Vicat methylimide, inwhich the impact modifier (A) was designed to give a high notched Izodimpact resistance. Example 136 shows that the same imide, whenalkylated, maintains good isotropic impact resistance (Gardener fallingdart impact, GVHIT), but loses notched Izod impact resistance. However,when the modifier (B) is specifically designed for the difference inmiscibility of the alkylated imide (Example 138), an excellent notchedIzod and falling dart impact resistance is maintained. These valuesdiminish in the unalkylated imide (Example 137). Examples 139 and 140show that as small amounts of PVDF are substituted for the alkylatedimide in the modifier B formulation, surprisingly large increases innotched Izod impact value are observed. At 10% PVDF, the impactresistance is high enough to remove 10% rubber modifier and stillmaintain good impact resistance (Example 141). Fixing the PVDF level at10% in the formulation in Example 140, and substituting modifier A againshows that lower, but good notched Izod impact values are stillobtained.

                                      TABLE XVI                                   __________________________________________________________________________                            Ratio                                                                              Notched   GVHIT                                             Imide        Imide/                                                                             Izod Tensile                                                                            Joules/                                                                             Tensile Prop.                    Exam-                                                                              Imide Vicat                                                                              meq/g   PVDF/                                                                              23° C.                                                                      Impact                                                                             cm (0.318-                                                                          % Elong.   DTUFL °C.      ple  Source                                                                              (°C.)/                                                                      total                                                                             Mod..sup.2                                                                        Mod. 0° C.                                                                       Joules/                                                                            cm-thick                                                                            @ Yield                                                                            Modulus                                                                             @ 180 kP.             No.  (Example)                                                                           Type.sup.1                                                                         acid                                                                              Type                                                                              (wt. %)                                                                            Joules/m                                                                           cm   plaque)                                                                             (break)                                                                            1000 kPa                                                                            (455                  __________________________________________________________________________                                                            kPa)                   135+                                                                              64    170/UC                                                                             0.624                                                                             A   60/00/40                                                                           106.5                                                                              17.4 22.8  8.6  2220  134                                                38.4            (20)       (149)                 136  65    160/C                                                                              0.002                                                                             A   60/00/40                                                                           53.4 25.2 25.3  5.4  2503  116                                                22.4            (67)       (130)                  137+                                                                              64    170/UC                                                                             0.624                                                                             B   60/00/40                                                                           64.6 10.5 9.38  6.5  2048  129                                                36.3            (16)       (144)                 138  65    160/C                                                                              0.002                                                                             B   60/00/40                                                                           206.7                                                                              29.4 26.2  6.0  2165  116                                                37.9            (52)       (132)                 139  65    160/C                                                                              0.002                                                                             B   55/05/40                                                                           242.4                                                                              27.1 31.0  5.6  1896  105                                                61.9            (75)       (122)                 140  65    160/C                                                                              0.002                                                                             B   50/10/40                                                                           331.1                                                                              32.4 31.5  5.1  1751   97                                                138.8           (89)       (113)                 141  65    160/C                                                                              0.002                                                                             B   60/10/30                                                                           180.5                                                                              25.6 30.5  5.3  2179  107                                                38.4            (88)       (121)                  142+                                                                              64    170/UC                                                                             0.624                                                                             A   60/10/40                                                                           185.3                                                                              21.0 >18   8.6  1972  107                                                36.3            (36)       (127)                 143  65    160/C                                                                              0.002                                                                             A   50/10/40                                                                           121.2                                                                              46.2 36.2  5.3  1862  101                                                46.5            (31)       (110)                 __________________________________________________________________________     .sup.1 Imides are all undried methyl imides. UC = unalkylated, C =            alkylated.                                                                    .sup.2 Modifier A = Butylacrylate (65%)//Styrene/Acrylonitrile (26/9%).       Modifier B = Butylacrylate (65%)//Styrene/Acrylonitrile (30/5%).         

EXAMPLES 144 TO 153

As noted by Kopchik (U.S. Pat. No. 4,255,322), methyl imides andpolyvinyl chloride (PVC) resins are miscible over a relatively widerange. However, we have found that high imidization levels, high imideacid levels, and changes in the polyvinyl chloride resins can causeimmiscibility in certain instances. Examples 144-153 illustrate thatreducing the acid and anhydride functionality of the imide can correctsuch immiscibility. Example 144 shows a 50/50 imide/polyvinyl chlorideblend (Geon® 103 PVC with a K value of 67) is only partially miscible,giving two sharply defined T_(g) values, while the same blend, made withalkylated imide (Example 145), is completely miscible.

However, when these same imides are melt blended with a lower molecularweight PVC (Example 146) (Geon 85, K value=62), both alkylated (Example147) and unalkylated (Example 146) imides are completely miscibile withthe PVC. Although the Geon 85 resin appears to be more miscibile withimides at lower imidization levels, only partial miscibility is observedwith this resin when imides having even higher imidization and acidlevels are blended with the PVC resin as in Example 148. This exampleshows one very broad and uneven T_(g) by DSC, indicating partialmiscibility, whereas the same imide, when alkylated (Example 149), showscomplete miscibility and one sharp T_(g). The indices of refraction ofthe imides having 90% imidization or greater are close enough to the PVCrefractive index so that appearance is not a conclusive factor.

Examples 150-153 show that the same enhanced miscibility seen withalkylated imides (Examples 144 and 145) is also seen in the twoformulations given below, which represent typical polyvinyl chloridesiding formulations for twin-screw extruder applications, and which arebased on the less-miscible Geon 103 PVC. In the blends and sidingformulations, we have also observed that the alkylated imide/PVCmaterials of the present invention show a better combination ofproperties than the unalkylated PVC/imide blends. A given, alkylatedPVC/imide blend may show less color generation, a lower initialviscosity, a slower viscosity rise (as measured by torque in Brabendermelt processing experiments), high impact resistance and heat distortionresistance.

    __________________________________________________________________________                  PVC Formulation I                                                                       PVC Formulation II                                    Component:    (PVC I)   (PVC II)                                              __________________________________________________________________________    Geon 103      100.0     100.0                                                 MMA/EA proc. aid.sup.1                                                                      0.5       1.0                                                   BA/S//S/MMA proc. aid.sup.2                                                                 1.0       0.5                                                   Me-Tin stabilizer                                                                           1.6       1.6                                                   Calcium stearate                                                                            1.3       1.3                                                   Paraffin wax  1.0       1.0                                                   TiO.sub.2     10.0      10.0                                                  __________________________________________________________________________     .sup.1 methyl methacrylate/ethyl acrylate                                     .sup.2 butyl acrylate/styrene//styrene/methyl methacrylate               

Results of these Examples are given in Table XVII.

                                      TABLE XVII                                  __________________________________________________________________________                              Blended                                                  Imide                                                                             Imide                                                                              Imide       PVC   Imide/                                                                            Observed                                  Exam-                                                                              Source                                                                            Vicat                                                                              T.sub.g                                                                           Imide                                                                             meq/g                                                                             Polymer/                                                                            Poly-                                                                             T.sub.g                                   ple  (Exam-                                                                            (°C.)/                                                                      (°C.)                                                                      % by                                                                              total                                                                             Polymer                                                                             mer (°C.) by                                                                    Appear-                              No.  ple)                                                                              Type.sup.1                                                                         DSC.sup.2                                                                         wt..sup.3                                                                         acid.sup.4                                                                        T.sub.g                                                                             Ratio                                                                             DCS  ance.sup.5                           __________________________________________________________________________     144+                                                                              62  167/UC                                                                             164 81  0.513                                                                             Geon 103/                                                                           50/50                                                                             156/101                                                                            OP/TL                                                          80                                                  145  63  157/C                                                                              158 84  0.011                                                                             Geon 103/                                                                           50/50                                                                             123  CL.sup.6                                                       80                                                   146+                                                                              62  167/UC                                                                             164 81  0.513                                                                             Geon 85/                                                                            50/50                                                                             106  CL.sup.6                                                       80                                                  147  63  157/C                                                                              158 84  0.011                                                                             Geon 85/                                                                            50/50                                                                             100  CL                                                             80                                                   148+                                                                              71  179/UC                                                                             175 91  0.798                                                                             Geon 85/                                                                            50/50                                                                             115  CL                                                             80                                                  149  72  165/C                                                                              163 90  0.002                                                                             Geon 85/                                                                            50/50                                                                             102  CL                                                             80                                                   150+                                                                              62  167/UC                                                                             164 81  0.513                                                                             PVC I 50/50                                                                             158/96                                                                             OP.sup.7                             151  63  157/C                                                                              158 84  0.011                                                                             PVC I 50/50                                                                             119  OP.sup.7                              152+                                                                              62  167/UC                                                                             164 81  0.513                                                                             PVC II                                                                              50/50                                                                             156/98                                                                             OP.sup.7                             153  63  157/C                                                                              158 84  0.011                                                                             PVC II                                                                              50/50                                                                             116  OP.sup.7                             __________________________________________________________________________     .sup.1 Imides are all undried methyl imides; UC = unalkylated, C =            alkylated.                                                                    .sup.2 Undried Imide.                                                         .sup.3 Imide weight% imidization level for methyl imides = 100 × (%     N/8.377%).                                                                    .sup.4 Milliequivalents of titratable acid in the imide per gram of sampl     (±ca. 0.020 meq/g titrated in MDC/MeOH  1/1).                              .sup.5 OP = opaque; TL = translucent; TP = transparent; CL = clear.           .sup.6 Appearance was clear with a trace of turbidity.                        .sup.7 PVC formulations I and II (see text) contain TiO.sub.2, and are        therefore opaque regardless of miscibility.                                   +Comparative                                                             

EXAMPLES 154 to 207

The following examples illustrate polyimide blends having 90/10 and10/90 weight ratios. These blends show that the enhancement ofproperties can occur for blends containing both small and large amountsof the imides having reduced acid and anhydride functionality. Theimides used were prepared in the manner of Examples 52 and 56,respectively; the imide sample treated according to the presentinvention contained 7.18 weight percent nitrogen and had aweight-average molecular weight of 129,000, and the comparative imidewithout reduction of the acid and anhydride functionality contained 6.87weight percent nitrogen and had a weight-average molecular weight of145,000. Additional properties of the imides, the polymers used forblending, and the blends are given in Table XVIII.

                                      TABLE XVIII                                 __________________________________________________________________________         Imide                                                                              Imide               Imide/                                                                            Observed                                    Exam-                                                                              Vicat                                                                              T.sub.g (°C.)                                                               Imide                                                                             meq/g      Poly-                                                                             T.sub.g (°C.)                        ple  (°C.)/                                                                      by   % by                                                                              total                                                                             Blended                                                                              mer by   Appear-                                No.  Type.sup.1                                                                         DSC.sup.1                                                                          wt..sup.1                                                                         acid.sup.1                                                                        Polymer.sup.8                                                                        Ratio                                                                             DCS.sup.1                                                                          ance.sup.2                             __________________________________________________________________________     154+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              --     100/0                                                                             168  CL                                     155  160/C                                                                              158  85.71                                                                             0.002                                                                             --     100/0                                                                             158  CL                                                            PVDF   0/100                                                                             CE.sup.3                                                                           OP/TL                                   156+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              PVDF   90/10                                                                             158.sup.3                                                                          OP                                     157  160/C                                                                              158  85.71                                                                             0.002                                                                             PVDF   90/10                                                                             146.sup.3                                                                          CL/H-                                   158+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              PVDF   10/90                                                                             92.sup.3                                                                           OP                                     159  160/C                                                                              158  85.71                                                                             0.002                                                                             PVDF   10/90                                                                             96   TL                                                            Sty/AN 0/100                                                                             113  CL                                      160+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              Sty/AN 90/10                                                                             163/110                                                                            CL/H                                   161  160C 158  85.71                                                                             0.002                                                                             Sty/AN 90/10                                                                             152  CL                                      162+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              Sty/AN 10/90                                                                             169/115                                                                            TL                                     163  160/C                                                                              158  85.71                                                                             0.002                                                                             Sty/AN 10/90                                                                             114  CL                                                            PETG   0/100                                                                             CE.sup.3                                                                           CL                                      164+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              PETG   90/10                                                                             168/89                                                                             CL/H-                                  165  160/C                                                                              158  85.71                                                                             0.002                                                                             PETG   90/10                                                                             158/90.sup.3                                                                       CL/H-                                   166+                                                                              170/UC                                                                             168  82.01                                                                             0.63                                                                              PETG   10/90                                                                             164/95.sup.3                                                                       TL/OP                                  167  160/C                                                                              158  85.71                                                                             0.002                                                                             PETG   10/90                                                                             156/96.sup.3                                                                       TL                                                            PC     0/100                                                                             152  CL                                      168+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             163  TL                                     169  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             155  CL/H-                                   170+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             169/148                                                                            OP                                     171  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             149  CL/H-                                                         PET    0/100                                                                             84.sup.3                                                                           OP/TL                                   172+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             155  TL                                     173  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             158/77                                                                             TL                                      174+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             161/873                                                                            OP                                     175  160/C                                                                              158  85.71                                                                             0.63       10/90                                                                             154/85.sup.3                                                                       OP/H                                                          PA     0/100                                                                             CE.sup.3                                                                           OP                                      176+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             153.sup.+                                                                          TL/OP                                  177  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             153.sup.4                                                                          OP                                       178+                                                                             170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             CE.sup.4                                                                           OP                                     179  160/C                                                                              158  85.71                                                                             0.63       10/90                                                                             152.sup.4                                                                          OP                                                            PS     0/100                                                                             191  CL                                      180+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             166/189                                                                            OP                                     181  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             159/181                                                                            OP                                      182+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             164/187                                                                            OP                                     183  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             158/188                                                                            OP                                                            Sty/MAH                                                                              0/100                                                                             130  CL                                      184+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             166/129                                                                            TP                                     185  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             157.sup.5                                                                          CL/H-                                   186+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             164/133                                                                            OP/H                                   187  160C 158  85.71                                                                             0.002      10/90                                                                             154/132                                                                            OP/H                                                          AN/MA/BD                                                                             0/100                                                                             --   TL                                      188+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             163/98                                                                             TL                                     189  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             153/81                                                                             TL                                      190+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             83.sup.6                                                                           TL                                     191  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             83.sup.6                                                                           TL                                                            EVA    0/100                                                                             --   TL                                      192+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             168/CE.sup.3                                                                       OP                                     193  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             157/CE.sup.3                                                                       OP                                      194+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             CE.sup.3                                                                           CL/H-                                  195  106/C                                                                              158  85.71                                                                             0.002      10/90                                                                             155/CE.sup.3                                                                       CL/H-                                                         PVC    0/100                                                                             --   CL                                      196+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             161.sup.7                                                                          DEC                                    197  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             152  TP                                      198+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             91.sup.7                                                                           DEC                                    199  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             102  CL                                                            Phenoxy                                                                              0/100                                                                             102  CL                                      200+                                                                              170/UC                                                                             168  82.01                                                                             0.63       90/10                                                                             163/112                                                                            CL                                     201  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             152  CL/H-                                   202+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             160/99                                                                             TL/CL                                  203  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             99   CL                                                            Nylon 12                                                                             0/100                                                                             --   TL                                     204  170/C                                                                              168  82.01                                                                             0.63       90/10                                                                             162/CE.sup.4                                                                       CL/TL                                  205  160/C                                                                              158  85.71                                                                             0.002      90/10                                                                             154/CE.sup.4                                                                       TL                                      206+                                                                              170/UC                                                                             168  82.01                                                                             0.63       10/90                                                                             CE.sup.4 /73                                                                       TL                                     207  160/C                                                                              158  85.71                                                                             0.002      10/90                                                                             CE.sup.4 /70                                                                       TL                                     __________________________________________________________________________     THE FOOTNOTES FOR TABLE NO. XVIII ARE AS FOLLOWS:                              .sup.1 As described for Table XVII. C = alkylated and UC = unalkylated.      .sup.2 CL = Clear; TP = Transparent; TL = Translucent; OP = Opaque; DEC =     Decomposed; H = Haze (H+ = Heavy Haze; H- = Slight Haze).                     .sup.3 Crystallization endotherm is observed in DSC.                          .sup.4 Crystallization endotherm obscures the T.sub.g                         .sup.5 Appears as though two T.sub.g 's are overlapping                       .sup.6 The Barex 210/Imide (90/10) blends degrade at a temp. on or around     the T.sub.g of the Imide on the Brabender melt mixing device                  .sup.7 Considerable polymer degradation is observed in all the Geon           85/imide blends, i.e., considerable color formation is observed, but the      alkylated imide/Geon 85 blends appear to be more stable.                      .sup.8 Polymers and sources:                                                  PVDF  Polyvinylidene fluoride (Kynar 720  Pennwalt Corp.)                     Sty/AN  75/25 Styrene/acrylonitrile copolymer (Tyril 1000  Dow Chemical       Co.)                                                                          PETG  Glycolmodified polyethylene terephthalate (Kodar A150 Eastman Kodak     Co.)                                                                          PC  polycarbonate, M.sub.w 20,000 (M39,  Mobay, Inc.)                         PET  Polyethylene terephthalate                                               PA  Polyacetal copolymer (M90  Celanese Corp.)                                PS  Polysulfone (Udel P1700  Union Carbide Corp.)                             Sty/MAH  Styrene/maleic anhydride copolymer (Dylark 332 Arco Chemical Co.     AN/MA/BD  Acrylonitrile/methyl acrylate/butadiene (Barex 210  Vistron         Corp.)                                                                        EVA  Ethylene/vinyl acetate copolymer (Elvax 750 E. I. DuPont de Nemours      Co., Inc.)                                                                    PVC  Polyvinyl chloride (Geon 85  BF Goodrich Co.)                            Phenoxy  Epichlorohydrinbisphenol A condensation polymer (PKHC  Union         Carbide Corp.)                                                                Nylon 12  (Grilamid  Emser Industries)                                   

EXAMPLES 208 to 219

The following examples illustrate blends of polyimide copolymers withpolystyrene (Sty) and polyphenylene oxide-high impact polystyrene blends(HIPS/PPO; Noryl®, General Electric). The polyimides having acid andanhydride functionality reduced according to the present invention werean imidized 90/10 methyl methacrylate/styrene (MMA/Sty) copolymer havinga nitrogen content of 4.95 weight percent (Example 209), and animidized, 73.5/24.5/2.0 methyl methacrylate/alphamethylstyrene/ethylacrylate (MMA/AMS/EA) terpolymer having a nitrogen content of 2.93weight percent (Example 211). The corresponding polymers not havingreduced acid and anhydride functionality (Examples 208 and 210)contained 4.90 and 3.08 weight percent nitrogen, respectively.Additional properties of the polyimides and blends are given in TableXIX.

                                      TABLE XIX                                   __________________________________________________________________________         Imide                                                                             Imide                                                                              Imide                    Oserved                                Exam-                                                                              Source                                                                            Vicat                                                                              T.sub.g (°C.)                                                              Imide                                                                             meq/g       Blending                                                                           T.sub.g (°C.)                   ple  (Exam-                                                                            (°C.)/                                                                      by  % by                                                                              total                                                                             Blended Tempera-                                                                           by    Appear-                          No.  ple)                                                                              Type.sup.1                                                                         DSC.sup.1                                                                         wt..sup.1                                                                         acid.sup.1                                                                        Polymer ture DSC.sup.1                                                                           ance.sup.3                       __________________________________________________________________________     208+                                                                              (2) 150/UC                                                                             148 77.8                                                                              0.620                                                                             (MMA/Sty)                                                                             --   148   CL                               209  (2) 144/C                                                                              142 78.57                                                                             0.018                                                                             (MMA/Sty)                                                                             --   142   CL                                210+                                                                              (2) 162/UC                                                                             160 58.0                                                                              0.736                                                                             (MMA/AMS/                                                                             --   160   CL                                                         EA                                                  211  (2) 150  147 55.49                                                                             0.030                                                                             (MMA/AMS/                                                                             --   147   CL                                                         EA                                                   212+                                                                              208 150/UC                                                                             148 77.8                                                                              0.620                                                                             Sty     450° F.                                                                     144/84                                                                              TL                               213  209 144/C                                                                              142 78.57                                                                             0.018                                                                             Sty     450° F.                                                                     134/85                                                                              TL                                214+                                                                              208 150/UC                                                                             148 77.8                                                                              0.736                                                                             HIPS/PPO                                                                              450° F.                                                                     144.sup.4                                                                           OP                               215  209 144/C                                                                              142 78.57                                                                             0.030                                                                             HIPS/PPO                                                                              450° F.                                                                     142.sup.4                                                                           OP                                216+                                                                              210 162/UC                                                                             160 58.0                                                                              0.736                                                                             Sty     450° F.                                                                     159/141/87                                                                          TL                               217  211 150/C                                                                              148 55.49                                                                             0.030                                                                             Sty     450° F.                                                                     139/85                                                                              TL                                218+                                                                              210 162/UC                                                                             160 58.0                                                                              0.736                                                                             HIPS/PPO                                                                              450° F.                                                                     162/138.sup.4                                                                       OP                               219  211 150/C                                                                              148 55.49                                                                             0.030                                                                             HIPS/PPO                                                                              450° F.                                                                     145.sup.4                                                                           OP                               __________________________________________________________________________     .sup.1 As described for Table XVIII, C = alkylated; UC = unalkylated          .sup.2 See text                                                               .sup.3 CL  Clear; TL = Translucent; OP = Clear                                .sup.4 Small enthalpic peak at 110° C. in DSC of Noryl blends is       unidentified                                                                  +Comparative                                                             

EXAMPLES 220 to 253

The following examples illustrate a series of 50/50polyimide/thermoplastic blends that were prepared in a Brabender mixerat the temperature indicated in the accompanying Table; an airatmosphere was used. The polyimide used is the polymethylimide F(Example 63), having a Vicat value of 157° C., a T_(g) of 158° C., 84%imidization, by weight, and a total acid and anhydride functionality of0.011 meq/g, reduced according to the present invention. The propertiesof the blends are given in Table XX.

                                      TABLE XX                                    __________________________________________________________________________                              Observed                                            Exam-                Blending                                                                           T.sub.g by                                          ple Blended          Tempera-                                                                           DSC  Appear-                                        No. Polymer.sup.5    ture (°C.)                                                                       ance                                           __________________________________________________________________________    220 Polyarylate      302° C.                                                                     155/192                                                                            OP                                             221 Polystyrene      232° C.                                                                     156/101                                                                            OP                                             222 Polycarbonate    246° C.                                                                     155.sup.2                                                                          OP                                                 (M50)                                                                     223 Polysulfone      316° C.                                                                     155/187                                                                            OP                                             224 Nylon 12         232° C.                                                                     45.sup.3                                                                           TL                                                 (Grilamid)                                                                225 Nylon 6          232° C.                                                                     156/53.sup.4                                                                       TL                                             226 Nylon 11         249° C.                                                                     153/51.sup.4                                                                       OP                                             227 Nylon 66         274° C.                                                                     157/64.sup.4                                                                       OP                                             228 PETG             221° C.                                                                     153/80                                                                             OP                                                 (6763)                                                                    229 Polybutylene terephthalate                                                                     223° C.                                                                     150/56.sup.4                                                                       OP                                             230 Polyethylene terephthalate                                                                     254° C.                                                                     153/86.sup.4                                                                       OP                                             231 Poly(methyl methacrylate)                                                                      232° C.                                                                     149/116                                                                            OP                                             232 Styrene/acrylonitrile (75/25)                                                                  450° C.                                                                     130  OP                                             233 Aromatic Nylon   260° C.                                                                     153  OP                                                 (Trogamid)                                                                234 PVC              199° C.                                                                     100  CL                                                 (Geon 85)                                                                 235 PETG             216° C.                                                                     149/95                                                                             OP                                                 (Kodar A 150)                                                             236 ABS              232° C.                                                                     128  TL                                             237 Polycarbonate    246° C.                                                                     152.sup.2                                                                          TL                                                 (M39)                                                                         Polyacetal       210° C.                                                                     CE.sup.3                                                                           OP                                                 (M90)                                                                     239 Styrene/maleic   232° C.                                                                     153/131                                                                            OP                                                 anhydride                                                                 240 Styrene/NH.sub.3 -Maleimide                                                                    246° C.                                                                     153  CL/H-                                          241 Styrene/N-Methyl Maleimide                                                                     246° C.                                                                     154/133                                                                            OP                                             242 alpha-Me Sty/Sty/AN copolymer                                                                  246° .sup.                                                                  138  CL                                             243 Polyphenylenesulfide (PPS)                                                                     302° C.                                                                     158/110                                                                            OP                                             244 Polyetherimide   327° C.                                                                     158/219                                                                            OP                                             245 MA/AN/BD         199° C.                                                                     142/82                                                                             TL                                             246 Phenoxy          193° C.                                                                     118  TL                                             247 Poly(ethylene/8% acrylic acid)                                                                 193° C.                                                                     158.sup.4                                                                          OP                                             248 Polyvinylidene fluoride                                                                        246° C.                                                                     78   CL                                             249 Chlorinated polyvinyl chloride                                                                 199° C.                                                                     149  OP/DEC                                         250 Polyethylene     199° C.                                                                     156.sup.4                                                                          TL/CL                                          251 Polypropylene    204° C.                                                                     CE.sup.4                                                                           OP                                             252 Ethylene/vinyl acetate                                                                         193° C.                                                                     156.sup.4                                                                          OP                                             253 Polyvinylidene chloride                                                                        193° C.                                                                     99   TL/CL                                          __________________________________________________________________________     .sup.1 OP  opaque, TL = translucent; CL = clear; H = haze (- is slight);      DEC = decomposition.                                                          .sup.2 Polycarbonate T.sub.g overlaps imide T.sub.g.                          .sup.3 Crystallization endotherm obscures imide T.sub.g.                      .sup.4 Crystallization endotherm observed in DSC.                             .sup.5 Polymers and Sources:                                                  Polyarylate is Ardel D100 (Union Carbide Corp.)                               Polystyrene is PS 656D (Dow Chemical Co.)                                     Polycarbonate M39 is M.sub.w 20,000 (Mobay Inc.)                              Polycarbonate M50 is M.sub.w 24,600 (Mobay Inc.)                              Polysulfone is UDEL P1700 (Union Carbide Corp.)                               Nylon 12 is Grilamid (Emser Industries)                                       Nylon 11 is BMNO (Rilsan Corp.)                                               Nylon 66 is Zytel 101 (E. I. duPont de Nemours & Co.)                         Nylon 6 is Fosta 446 (American Hoechst Corp.)                                 PETG 6763 is Glycol modified polyethylene terephthalate (Eastman Kodak        Co.)                                                                          Polybutylene terephthalate is Celanex 2002 (Celanese Corp.)                   Aromatic Nylon is Trogamid T (KayFries Co.)                                   PVC is polyvinyl chloride Geon 85 (BF Goodrich Co.)                           PETG Kodar A150 is glycolmodified polyethylene terephthalate (Eastman         Kodak Co.)                                                                    ABS is butadiene//acrylonitrile/styrene Abson 89140 (Mobay Inc.)              Polyacetal M90 is a product of Celanese Corp.                                 Polyvinylidene chloride is Experimental PVDC Resin XU32009.00 (Dow            Chemical Co.)                                                                 Other polymer descriptions may be found in the footnotes to Table XVIII. 

EXAMPLE 254

In a manner similar to that of Examples 242-253, a 50/50 blend of thepolyimide from Example 20 with alpha-methylstyrene/acrylonitrilecopolymer was prepared at 246° C.; the resulting clear blend had asingle T_(g) of 138° C.

EXAMPLE 255

In a manner similar to that of Example 233 a 50/50 blend of polyimide(having a Vicat value of 160° C., a T_(g) of 158° C.; 82% imidizationand 0.002 meq/g total acid and anhydride functionality, reducedaccording to the present invention) with Noryl® (polyphenyleneoxide-high impact polystyrene blend) was prepared. The resulting opaqueblend showed T_(g) values at 158° C. and 138° C.

In a manner similar to the above examples, copolymers of styrene andmaleimide, containing residual maleic anhydride functionality, such asDylark® DKB-162, in which approximately 14% of the anhydridefunctionality remains (see U.S. Pat. No. 4,458,046- Example 1), may betreated to decrease or substantially eliminate the anhydridefunctionality using the conditions of Examples 7 and 30.

Polymeric imides resulting from condensation of dianhydrides anddiamines, including the generic class of polyimides referred to aspolyetherimides, which contain residual acid functionality, may also bereacted with the agents disclosed above, using the conditions ofExamples 7 and 30, where the extrusion temperature is about 350°-400°C., to give polyimides with reduced levels of acid functionality.

Further, polymeric imides resulting from copolymerization of maleimideswith other vinyl monomers, such as copolymers of maleimide or N-phenylmaleimide and styrene and/or MMA, in which partial hydrolysis hasoccured to give maleamic acids, diacids, or anhydrides, may be treatedwith the agents disclosed above, using the conditions in Examples 7 or30, to give decreased levels of acid and anhydride functionality.

Adhesion-enhanced impact resistance is expected in blends ofpolycarbonates with impact modifiers, and the imides of the presentinvention; such blends using untreated imides are disclosed by Mueller(U. S. Pat. No. 4.254,232). Improved miscibility leads to betterbonding, and thus to improved impact resistance.

In general, all imides disclosed in U.S. Pat. No. 4,246,374, herebyincorporated by reference, especially those polymeric imides containingup to 20% of the lower alkyl acrylates, which contain any residual acidor anhydride functionality, may be effectively treated by the methodsdisclosed above, such as the method described in Examples 7 and 30, togive polymeric imides with reduced or substantially eliminated acidfunctionality.

We claim:
 1. A blend of at least one thermoplastic polymer and a secondpolymer containing glutarimide units wherein the degree of imidization,by weight, on said polymer is from about 1% to about 95%, and the degreeof imidization and the acid and anhydride functionality on said polymer,expressed in milliequivalents per gram of total imidizable and imidizedpolymer units are as set forth below;

    ______________________________________                                        when the degree of imidizaton                                                                    the milliequivalents of acid                               on said polymer is and anhydride per gram are                                 ______________________________________                                        from about 1% to about 10%                                                                       0 to about 0.20                                            above about 10% to about 20%                                                                     0 to about 0.28                                            above about 20% to about 30%                                                                     0 to about 0.32                                            above about 30% to about 40%                                                                     0 to about 0.31                                            above about 40% to about 50%                                                                     0 to about 0.28                                            above about 50% to about 60%                                                                     0 to about 0.28                                            above about 60% to about 70%                                                                     0 to about 0.27                                            above about 70% to about 80%                                                                     0 to about 0.28                                            above about 80% to about 90%                                                                     0 to about 0.33                                            and above about 90% to about 95%                                                                  0 to about 0.40.                                          ______________________________________                                    


2. A blend according to claim 1 wherein said second polymer is presentin an amount of from about 1% to about 99%, based on the total weight ofsaid thermoplastic polymer plus said second polymer.
 3. A blendaccording to claim 1 wherein said second polymer is present in an amountof up to about 50% based on the total weight of said thermoplasticpolymer plus said second polymer.
 4. A blend according to claim 1wherein said second polymer is present in an amount of up to about 50%to about 99%, based on the total weight of said thermoplastic polymerplus said second polymer.
 5. A blend according to claim 1 wherein saidthermoplastic polymer is a styrene/acrylonitrile copolymer or a stagedpolymer having a butadiene core followed by an outer stage which is astyrene/acrylonitrile copolymer.
 6. A blend according to claim 1 whereinsaid thermoplastic polymer is a copolymer of methyl styrene andacrylonitrile.
 7. A blend according to claim 1 wherein saidthermoplastic polymer is polycarbonate.
 8. A blend according to claim 1wherein said thermoplastic polymer is polyvinylidene fluoride orpolyvinylidene chloride.
 9. A blend according to claim 1 wherein saidthermoplastic polymer is a polyalkylene terephthalate.
 10. A blendaccording to claim 1 wherein said thermoplastic polyvinyl chloride orchlorinated polyvinyl chloride.
 11. A blend according to claim 1 whereinsaid thermoplastic polymer is a polyamide.
 12. A blend according toclaim 1 wherein said thermoplastic polymer is polystyrene.
 13. A blendaccording to claim 1 wherein said thermoplastic polymer is a copolymerof epichlorohydrin and bisphenol A.
 14. A blend according to claim 1wherein said thermoplastic polymer is a blend of high impact polystyreneand polyphenylene oxide.
 15. A blend according to claim 1 wherein saidthermoplastic polymer is a copolymer of bisphenol-A and isophthalicand/or terephthalic acids.
 16. A blend according to claim 1 wherein saidthermoplastic polymer is a multi-stage polymer.
 17. A blend according toclaim 1 wherein said second polymer is a multi-stage polymer and theoutermost stage of said second polymer contains said imide units. 18.The blend of claim 1 further including filler materials selected fromminerals, glass and metals.
 19. The blend of claim 18 wherein themineral is talc.
 20. The blend of claim 1 further including additivesselected from the flame retardants, blowing agents, antioxidants,thermostabilizers, pigments, flatting agents, lubricants, antistaticagents, conductive materials, toners and ultraviolet stabilizers.